Do you have a reliable way to reproduce? Can you try the 1.9.1.p4 beta? It has a fix that might address this, but I'm unable to reproduce here to test it.
Hi Alex!
I have not a reliable way to reproduce, sadly. But it seems to be connected to prefabs within prefabs, and global variants. It is almost always a global variant that has been swapped out to another global variant. Sometimes it happens when I copy actions inside a prefab, and sometimes it just happens.
I tired the beta but the issue still remains. In the old patch the issue went away when I restarted unity but but it does not fix it any more.
So right now I am stuck. The variable looks good in prefab mode, but when I look at the variable in the editor after, it has magically swapped to another global (It's exactly like if I pressed "edit instance" and changed the variable, except... I have not done that. I even have "confirm editing prefab instances" checked in the settings to avoid have editing a prefab by mistake.