dgonzalez, your comment was pointing in the right direction.
I had the provisionin tasks created under my personal account. Even though I have admin rights, I have a limited scope. My scope includes PXE added devices, so I didn’t question that further.
Now we created a dedicated user with admin rights and no scope limitations and the templates are being picked up as expected.
I already had opened a support case a year ago, and the problem couldn’t get solved. I raised a new case recently, this time the support engineer saw the issue during our first web meeting.
Very annoying bug that caused a lot of frustration for a long time.