The business has a requirement to keep fixversions on issues and their sub-tasks in sync.
I utilized the post-function to copy fixversions from a parent to a sub-tasks when the sub-task is created (this is not automation and works fine).
However, when the sub-tasks have already been created, if a user changes the fixversions on a parent, i need the fixversions to get copied down into the child sub-task.
Since the fix versions is a read only field on the sub-task I can't do a regular edit, and instead need to used the advanced section to copy down the fix versions from the parent.
Here is my automation rule
Here is the error I receive
