[CrushinFelt]

Yes people check all three streets with the nuts when they don't have a redraw (most would c/r the turn rather than c/c but this line isn't too uncommon).

More to the point is that you're probably not getting 3 streets of value from a lower set (the most likely hand to pay you off), and the rest of their range is big draws that missed and two-pair + FD hands. That part of their range is not calling a 3rd bet in an unraised pot enough to warrant betting here.

Finally, the min-raise on the river can absolutely not be a bluff. It's an unraised pot and you've hammered all three streets. There's no way they expect you to fold to a min raise.

You're right that the line is uncommon for the nuts, but the river min-raise is even less common as a bluff (especially in an unraised pot).