There is definitely something fishy going on with CPUs right now...
Flew COS-BOS-COS with my wife last week. I was on a mixed fare V&T ticket while my wife was flying on miles - 2 separate PNRs. I should mention that my wife's flights were booked into Business (IN) bucket so she was already sitting up front while I played the CPU lottery.
On the BOS-DEN return (a 739 w/ 16 F seats), my wife sat next to a Gold who admitted to her that he was really surprised that he got upgraded. He did not use any instrument or miles and was CPU'd. I sat in 21C and ended up #9 on the UG list
(Nobody boarded when the GA called GS so I doubt there were that many with higher status ahead of me).
For the short DEN-COS hop (CR7), my wife was in 2C and I was #1 on the UG list with 2 empty seats. I sat in 3B. I monitored the United app expecting the GA to come on board and move me up - it never happened. A guy boards last minute (he missed his earlier flight) and the GA just waves him into 1C. 2A went out empty. Apparently the GA never processed the UG list at all. Not a big deal for a 20 min flight but it irritates me when the process isn't followed.
Leads me to start questioning what other things aren't happening that should be?