USA: 1 dollar, 2020, km732, a coin with no mint mark?

N#193553

Since I'm putting a huge amount of dollars into my collection, I wondered about this year line

is it supposed to be collectors not knowing the date and the mint is on the rim, or if the printing on the rim is not readable?

All of those coins start out with the mint mark on the edge. On coins that circulate (typically in vending machines) the edge marking wears down quickly sometimes making them unreadable. Regardless there should be no year line without a mint mark. That line needs to be deleted and members moved to the Undetermined year line which won't show up on the coin page for those without that year line in their collection.

Submit the request in the Catalog forum.