Pain suggests a site reaction, I can’t think of another explanation. This certainly occurs, e.g.:
https://www.aaaai.org/allergist-resources/ask-the-expert/answers/2023/insulin
Site reactions themselves are know to cause a reduction in insulin sensitivity with pumps certainly going back to 2010:
There is a lot of research between 2010 and today. The balance seems to be that the catheter (or, for Omnipod, the pod) can’t be relied on past 3 days and starts to fail at 2 days but this varies enormously between diabetics In addition, as the first paper suggests, there is also variation between insulins.
So the idea that a particular insulin fails to work with a particular pump seems unlikely; Occam’s razor. We know that particular insulins fail with particular people! An endo will most likely respond to the information by swapping to a different but similar acting insulin. To me any demonstrable site reaction, including pain, seems a sure-fire reason to swap. If that means a formulary exception then I don’t imagine that would be hard though in the US the cost must also be considered.
This second link comes from this thread, which is also discussing site reactions and is certainly worth reading: