Take a look at your FL policy to see it covered full months, i.e. that it would have continued coverage until the end of Dec. (I assume you didn't become an MN resident until after Dec 1.) Also, did you explicitly cancel the FL coverage in Dec?
The APTC tax form does ask for what states you resided in. Your issue is whether you have to repay for the month you moved to MN.
One item from www.healthinsurance.org strongly suggests that your FL coverage would have to have been active through at least the end of December:
Outside of open enrollment (ie, if you’re enrolling due to a qualifying event), the regular schedule in all but two states works like this (unless you’re enrolling due to loss of coverage, marriage, or adding a dependent; these scenarios are discussed below:(
So an enrollment completed on May 9 would have a June 1 effective date, but an enrollment completed on May 17 would have a July 1 effective date.