A lot of people here are saying things are mislabeled, but every single solar panel comes with a datasheet that shows its Voc and temperature coefficient.

Solar panel manufactures can’t give you a hard maximum on voltage because temperature will make that vary. Anyone who is buying solar panels without understanding the temperature coefficient shouldn’t be buying solar panels. It’s not hard to understand and there are hundreds of guides out there explaining it if you just search for terms on the datasheet.