Cool, you didn’t use the gactions command yet?
I removed all my projects and started new one from ground up. Everything worked as should.
Ok 1 issue less 
Update from google support:
Blockquote
Hi,
Upon testing on our end, we are glad to inform you that this issue has been fixed. Kindly try on your end.
Thank You,
Goldwin
Actions on Google Support Team
Blockquote
Well that’s promising…
It’s odd that there hasn’t been more products affected and the resulting noise about the problem… 5 or 6 people here…
On the Sync Failure with 20 devices issue I just got this from Google (well, looks like it was half an hour ago, but I just spotted it):
Dear Partner,
Thank you for contacting the Actions on Google Support Team.
We are facing a generalized issue with this.
A bug has already been opened and our Engineering Team will take care to fix this issue.
Another partner reported the bug for us and there is a workaround:“After the 17 devices synced, I added an 18th device that was previously failing. It worked.
I then allowed 17 more devices to sync. Then I synced another 17, and another 17, and so on, until all the devices were synced.
This seemed to work fine.
Too many new devices in any sync causes the backend service call to fail.
My guess is, given the long response time on initial sync, I think the backend is timing out and returning a 500 error. That’s why smaller incremental syncs may work.”Sorry for the inconvenience
So, they know about it and are working on it.
good to hear, thnx for feedback, although in my case, when i first link 19 devices and update the config
i am not able to sync correctly when more entities are exposed from HA
i am not able to sync correctly when more entities are exposed from HA
My suspicion is that there is a method in the API to just expose the new entities in a request, rather than all of them (an add rather than update) which neither the “sync devices” voice command or HA’s google_assistant.request_sync system use.
If I have time (and this lasts for too long) I might take a look and throw something together (shouldn’t be that difficult to code). For now since they are aware of it and it can’t be that small an issue hopefully it’ll be fixed soon and we won’t need to write a workaround.
Yes indeed, but will have the approach of a limited amount each time, we can have room back maybe
btw, this command , is that doint exactly the same as “sync my devices” ? that would be handy
google_assistant.request_sync
didnt know that
As luck would have it the first time I ever try to setup Google Assistant with HA was 3 days ago when this bug popped up. I got it to work using the workaround and then after much frustration figured out that my Home mini was associated to my premium Google account and assistant to my personal account. So I figured out I had to setup Google assistant again for that account and add two project and API keys into my configuration.yaml. The second time I setup on the second account I did not need to do the workaround.
Now it works for both accounts. I set expose_by_default to true and have nearly 50 items that could sync. I’m not sure how Google or HA handles having hue bulbs added in Google Assistant and also in HA (same with wemo) but it seems to work OK and not show duplicates. The odd thing is that the first account I setup (personal one) has 32 devices sync’d of my estimated 50 total but the second account I setup sync’d 31 devices. I’ve not tried removing and re syncing but it is strange that the cap of devices syncd is not the same between both accounts on the same HA setup.
As an FYI I am not using the rooms feature and like I mentioned expose everything by default just to get this working initially.
So, what’s your question/issue? 
My issue is that one account exposes 32 devices and the other exposes 31 on the same HA setup but I have around 50 that should be exposed. None of this aligns with the 20 limit I am reading above and is not even consistent within my own setup where the only difference is a different Google account. I am providing more information to this thread on what I am observing to see if a consistent pattern emerges on setup and settings.
you know that there are caching issues? you dont see the it instantly changing
i was testing yesterday, although link was succesfull, devices appeared only day after
also note : scenes/scrips, are devices you actually not see
I did not know about caching issues. I deleted the account with 31 devices and resync’d and now it has 32 devices so it appears in my case 32 is the limit as that is what the first account had. My configuration.yaml looks like this. I’m not sure if I should even do it this way as documentation didn’t indicate this would work but it now works from both google assistant accounts and on my google home mini.
google_assistant:
project_id: xxxxxxxxxxx
api_key: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
exposed_domains:
- switch
- light
- group
- cover
- scene
expose_by_default: true
google_assistant:
project_id: yyyyyyyyyyyyyyyyyyyy
api_key: yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyk
exposed_domains:
- switch
- light
- group
- cover
- scene
expose_by_default: truehmm, so you have 2 x times google_assistant in your setup? i though that wasnt possible, only 1 project
also, 32 is not the limit, i have 62 x devices exposed , and probaly some more
Yeah I didn’t think it was possible either but it appears to be working. As explained above I have a personal account and family account which has my premium YouTube membership. My personal account is on my phone but my Google home mini is primarily tied to my family account with the premium membership. I do this so I can use Ok Google to play the vast collection of Music I pay for. Even if I add my personal account so both are on there the Google home mini does not see any of the home control devices I first setup on my personal account. I went through the entire process of setup again on my family account, created new API key, and through the home app added the test app that shows up once it configured on Google’s end. I created two google assistant entries in configuration.yaml with different api keys and different project keys. Now both accounts have the home control and both seem to cap off at 32 devices sync’d if I let is sync everything. I still have not tried to manually put devices in rooms. I don’t really like the “rooms” concept of Google home because I can only put a light in one room. I can’t put a device in “Bedroom” and in another room called “Upstairs” whereas with Alexa I can put multiple devices in multiple groups. I would much rather group everything together in HA and expose “UPSTAIRS” as a switch to Google Home.
Interesting, you know that if you expose entities to an Google home device, if you put the devices and the Google mini, in the same house… You can share that house to another Gmail address…so the other Gmail account will also see the devices… And also the Google mini, isn’t that better for you?
But anyway, 2 projects from one HA is interesting, that should maybe solve my case… For example , my mini device is downstairs, so I have a switch called “music” , so if I say “music on”, then my receiver in downstairs zone 1 strarts playing…
I also want to say “music on” to my second Google device, upstairs, but 2 entitys with same name is offcourse not possible… So maybe I can indeed expose a second project to my second mini device… And then exposing entitys with same name, but actually doing complete different things,
That didn’t work for me. I thought that would work too. I added my personal account to the Google Home Mini from the home app doing the whole invite process and accepting. It asked if I wanted to do voice match which I said no on. Perhaps that is why it defaults back to the family account when using the Mini and only sees the HA devices (previously none) when on the personal account. I “assumed” that if I had done the voice match and that actually worked well then when I talked it would use my personal account with the HA devices associated but then if my wife talks it would use the family account without the associated devices. Now both accounts are associated so it is not a problem. Maybe I will setup voice match and turn off my wife’s ability to control certain things on april fools or rename them to funny things “Ok Google, turn on my husband” to control the bedroom light 
Let me know how it works out for you to separate. I was pleasantly surprised two google assistant entries worked.
On a slight rant I am exceptionally irritated trying to use the Google console when dealing with a secondary account. It kept defaulting back to my original account when I copy/paste links in from the HA instructions and the worse was it would immediately redirect to a URL with my first accounts project name. If you click the picture to change to a secondary Google account you get a permission denied you are not authorized error because it tries to load that unique URL with the unique project name from the first account. Those URL links dont even follow the typical Google way of seperating accounts .com/u/0/ and .com/u/1/ What you have to do is manually trim the end of the URL string of the project name from the first account and add in ?authuser=1 to get the second account. Ok rant over.