Michigan Return Under Review

Well, I e-filed Fed/Mi taxes on 3/4.
Amazingly, got my Fed refund on 3/11
(contrasted with a 4-month delay last year!).

When I checked on my Mi refund, it says "under review."

TT said my audit risk is very low. I do not itemize.

So I am mystified by the designation.

Is there a likely/common issue? Any clues?

Mel