This may be by design and something I’ve missed but I seem to have found out that an entities state is case sensitive especially when it comes to Lovelace.
I have a device_tracker entity with the state of home and it displays great in the standard UI but doesn’t display in Lovelace UNLESS I change its state to Home.
I found that the case and the state doesn’t matter in standard UI I can have it as home or Home and it still displays.
I don’t think this is a code issue as such, Try it yourself. Change the state of entity from lowercase to uppercase in Developer Tools>States and see if the entity still working in standard UI and then Lovelace UI.
I see what you are saying now but it works exactly the opposite for me…
If the device tracker is in state ‘home’ it works in both UI. If it’s ‘Home’ then it works in the legacy UI but not in Lovelace.
So, at least in my case, the default way the device tracker states get created (home. not_home) work fine in mine in both legacy and Lovelace. I’m not sure why yours would be different. Do you have any type of customization?
I think I’ve found the issue. The state filters in Lovelace had there first letters capitialised which is why they weren’t being picked in the UI. Set all to lowercase and now working in both UI’s.