Hello,
So I have already rules setup in place for when an sub-task issue is created/edited/deleted, and these work perfectly. Here's one example below:

However the only thing left is to get a rule working for when a sub-task is MOVED / changed to a different Parent issue, and to continue with updating Parent total Estimate based on Estimates from sub-tasks.
I've attempted using Parent Link from the Issue Updated trigger but unfortunately this does nothing.
So looking for an answer to help with this please : )