Hang on a sec. I think the voter registration exceeding 100% of residents is just the registration. It looks like this is because they're not purging voters who are inactive, dead, or moved away, I don't think this is unique to 2020. Also, none of the states listed were swing states like Pennsylvania, Nevada, or Arizona.

Do we know if there are any counties where actual votes exceeded the residential population? That would be much more interesting.