I got the same email yesterday. Had a slight panic but eventually realised (I hope) that it was referring to the .com site.
I have a US Handmade account too, but never ever listed anything on it. I'm hoping it was just because of that. I couldn't see any changes to my UK Handmade listings or their visibility. And yeh, the time of year is extremely frustrating. They say not to edit certain fields whilst this is ongoing and at the same time seem to be making a hash of the move meaning we want to go in and fix them - though I can't see any changes to the 'Product Type' column yet.
I don't have time to go through 3000 listings to see if they are different from what's in that report. Also I can't understand why the report has the ASIN field empty for my Handmade listings, but the listings all have ASINs. Am I meant to go and manually add them to the report and upload it? This seems such a mess.