The issue seems to be related to the starred courses block, since when this block is deleted the message no longer appears.
I linked it to the fact that I had deleted some of her starred courses last week and believe this is what is causing the message to show. I tested this with my own dashboard, deleting one of my starred courses and the message appeared immediately.
However even after restoring the deleted course the message remains when the starred courses block is added.
Is there anything that can be done to resolve this? Or do we need to check that courses are always unstarred before deleting them?
Starred block Version 2018120300