Hay All, not sure if its a bug or not, but I just spent 2 hours trying to find why an automation wasn’t working, only to find I had made a spelling mistake! The annoying thing is the configuration checker didn’t spot it, and there were no errors during execution. I had spelt milliseconds with one “L”. 
Thanks
The configuration checker checks for correct syntax, it is not a spelling checker.
Config checker has no way to know of every single possible custom attribute any random service call could make.
The Home Assistant VSCode plugin would have highlighted that for you!
Also, the logs would have given an error saying there was no key for “miliseconds” or something like that 
But as Francis says, the config checker just makes sure what you have is valid YAML so things don’t all crash and burn and break the entire system on next reboot.
Ah, OK, I had it in my mind that words e.g “seconds”, “minutes”, milliseconds" when used with “delay” would be something like reserved words, and thus get picked up by the config checker.
I shall be more careful next time 
That should have produced a warning or error.
Is this Mick Taylor from Diever?
No, sorry!