Hi @Jonathan_Austin and thank you for taking time to repor this issue!
If I understood correctly, what you are experiencing is the same behaviour reported here: Avoid subtasks from duplicating when creating a project from a template Correct?
If yes, please have a look at my colleague’s post here to see if the workaround provided helps you in the meantime.
If it’s OK with you, I’m going to merge your post with this main thread to keep you posted in one place when we receive an update from the Product Team.
Looking forward to your reply!