Offer buttons disappear after a few hours

It’s possible something like that is happening, but I am not familiar with that plugin so it’s tough to say what’s going on.

One way or another, though, the offer must be getting disabled, so if you’re not deliberately doing that then you’re probably on the right track.

Does that plugin show you everything it’s about to update? You may need to check closely to make sure the meta data for offers is not getting included.