My playing partner and I in a 2-player game just noticed that if we both buy the 'Inheritance' card, _and_ both move our 'Estate token' to the same action card (although we don't actually see the 'token', but I guess that's less important), then the person who bought it last effectively kicks off the previous person from using that ability.
In our case, I bought Inheritance first, and put my token on the Plaza card. I noticed while waiting for my partner to finish her play there was an estate card in my hand, and it mentions the 'Play the card with your Estate token, leaving it there' capability. However, one it's my turn, the text on my Estate cards switches to the normal image, and I do not have the Plaza capability I expected.
I'm guessing this is a bug, but please correct me if I'm wrong.
That indeed sounds like a bug. Do you remember your opponent's name (which would help finding the game and checking what happened). One potential error I made a few times is that I took so long to decide which card to inherit that I did not actually click on Inheritance at all but only the card I wanted to inherit, thus simply buying it.