We have a regular 3-tier hierarchy Epic,->story->sub-tasks.
The use-case is that occasionally, the parent of sub-tasks changes (move sub-task to different parent) and in this case, we would like to update the fixVersion value of the sub-task with the value of fixVersion of the new/updated parent.
We are trying to use a rather simple automation for this:

However, the result is that it copies the fixVersion from the original parent and not the new parent.
So, if original parent TEST-1 has fixVersion Release 1 and TEST-2 has fixVersion Release 2, moving a sub-task from TEST-1 to TEST-2 copies the Release 1 (which in fact is the version the sub-task already has), moving it back from TEST-2 to TEST-1, the sub-task gets Release 2 (not a likely use-case at all, but included to demonstrate the point).
I realize, it might not be correct usage of the hierarchy, but the team requires fixVersion on sub-tasks for other statistical reasons.
I tend to think this is a bug, since the trigger is the change itself (i.e. it has happened), but obviously it does not work as anticipated by me.
Does anyone have a solution for this?