I wasn't able to find any other reports of this issue, so let me post it and see if anyone else has experienced this.
Occasionally when I have worked on a prefab object FSM (by double clicking on the asset and opening it up in its own scene), I will save and return to my main scene file to find that some of the variables in the instance of the prefab have been jumbled up. ie 'Int_Variable_A' inside an action has been switched out for 'Int_Variable_B'. If I return back into my prefab scene, all the variables there are correct. Jumping back into my main scene file again, they are still jumbled.
Note this is not an issue with me overriding values on an instance of a prefab in my main scene file. This happens even if the prefab doesn't exist at all in the main scene hierarchy (and is created freshly by a playmaker 'create object' action after hitting play).
Some additional info:
-When the issue occurs it will soemtimes jumble up lots of different variables in a few states and actions.
-As the variables are switched randomly, 'luckily' it breaks my scene so catastrophically that its usually very apparent that the issue has occurred so I know to look for it.
-Its pretty infrequent that I get this issue.. but does pop up every few days
-The mix up does persist into a build of the game. Its not just an issue in my unity scene.
-Weirdly, if I change the problematic variable in my action (in the prefab file) to something else, save, then change it back to the correct variable and click save it does NOT correct/refresh the problem in my scene file.
-Luckily though I do have a very easy fix. If I create an empty state in my prefab FSM, click save, then delete the empty state and click save again, when I return to the main scene file this completely resolves the issue.
In my screenshot 'Prefab' You see the correct variable 'FloorManager_go'.
In the screenshot 'SceneInstance' you see what this same action looks like on the instance of the prefab- 'Current_Money_go' is in its place. Which is another random variable which was in use somewhere else in the prefab.
Sorry I don't have any exact repro steps to reliably reproduce it.. but I did make a video of the issue last time I saw that which I can provide if it helps. Thanks!