As an update/bump, I DID find there is more to this bug. It seems to impact more than just Hide. It seems to impact a few Bonus Actions that have some kind of condition attached to them.
I also happened to find two odd work-arounds:
1) Selecting another companion then re-selecting the character whose turn it is seems to refresh the abilities, allowing you to use them.
2) Waiting ~30 seconds (although why would you do that when you could do option 1)
