The Strangest Hand I've Ever Seen

Was at the table (not involved) for this hand, which has to be one of the weirdest hands I've seen.

$2/$4, Cake Poker skin, Full Ring, 9 players.

UTG calls, UTG+1 folds, UTG+2 calls, MP1 calls, HJ raises , CO calls, Button calls, SB folds, BB calls, UTG 3-bets, UTG+2 calls, MP1 folds, HJ calls, CO calls, Button caps, all 5 players remaining call.

Yes, if you are counting that is:

• 6 ways capped preflop (with some dead money from MP1 and SB to boot!)
• An UTG limp-re-raiser
• A button coldcall-capper

Flop: K22, two-tone

BB checks, UTG checks, UTG+2 checks, HJ checks, CO bets, Button folds, BB folds, UTG calls, UTG+2 folds, HJ folds.

Yes, if you are still counting, that is:

• CO betting into the coldcall-capper
• The coldcall-capper folding to a single bet into a 25-ish bet pot on a K-high flop.
• That single CO bet getting four folds in a 25-ish bet pot, with only the UTG LRR-er calling

The turn and river were a blank T and a J which completed the flush. UTG check/called the turn and check/folded the river.

Yes, in addition to everything else in the hand:

• CO won a 15 BB pot without a showdown, with a single bet on the river.

WTF? Collusion? Or just overall stupidity?

To further cloud the possible issue around collusion (I will use the labels LRR-er and CC-capper to label the players below):

• The very next hand, LRR-er and CC-capper put 4 bets in preflop (trapping one player in the middle) and LRR-er folded the T72 two-tone flop for a single bet.
• Another hand transipered about 1 revolution later where a 17 BB pot was won without a showdown, with a single bet on the river (LRR-er was one of the folders on the river, CC-capper not involved)