This is probably hard to solve as long as it is not reproducable. Can you reproduce this in another app? That would help a lot, because then Mendix will help you solve it. This module is supported by them.
Here may be a quick fix by Chris Franson in his marketplace-comment June 15, 2021, 8:35PM:
MAKE SURE YOU SELECT PROJECT--> CLEAN DEPLOYMENT DIRECTORY
He does not mention why, but the snagg your hit just might be the reason.
I found the problem and have everything working again.
If it helps someone else, the problem was I had the association incorrect. I had the association incorrect, It should be a 1:Many from the import entity to the data entity.
Thanks