That possibility had occurred to me too. On the other hand, many (most?) people don't think to cancel their voter registration when they move (I didn't, I live in the same county now and still vote in my old precinct.) Perhaps the current controversy reminded some to take care of that detail, instead of assuming that the registrars would some how do it automatically?
I have moved many times and never thought to cancel my voter registration. Thought re registering elsewhere cancelled it...
Fraudulent votes follow moving vans being loaded.