Hand takes place between V1, a regular, and V2, clearly an unexperienced player.
Single raise pot.
Flop: JJ7r

V1 bets 1/2 pot, V2 calls

Turn: JJ76r

V1 bets 1/2 pot, V2 raises x5, V1 calls. V2 proudly tables his [J5]. The whole table goes WTF, V2 realises and says: "omg i thought we were on the river". Dealer explains the hand has to continue, V2 keeps apologizing to everybody, he has about 60bbs left.

River: JJ725

V1 shows KJ and folds. V2 apologizes again.

I don't get why V1 folded.

Because he can see V2's hand.

Yeah, sorry, was on my phone and didn't notice V2 rivered a boat. Thought V1 was just folding a better hand out of courtesy or something. NVM.

I wouldn't play at this room

After that hand I would have cashed out and left

Any room where the turn card changes after the river has been dealt has to be badly run/a scam

Folks (especially beginners) accidently expose their hands often enough for this not to be thought of as rare. Sucking out a FH (5 on the river) makes it less common I guess.

V2 apologizes for missing out on an extra 60bb ... GL

oops

I have seen this happen a couple of times on the river, they think V checked etc.. but never on the turn like this.

Just gotta play long enough. I've seen some funny hands with prematurely exposed cards, too.

One time UTG limped in the 1 seat and it folded to the blinds, who thought it was a chop and expose their cards in a way UTG can easily see them. BB has 23o, SB has garbage too. Upon being told they can't chop, SB completes, BB checks and they see a flop of J82dd, BB bets, UTG calls, SB folds. Turn 4 goes check/check. River 2d and BB bets again, gets raised and calls to see a flush.

Another time the board is something like J886 on the turn. A player bets, gets raised, and then while he's tanking he purposefully exposes his QJ, but then he calls with big stacks left behind! River bricks and goes check/check and he wins.

I had a similar fun hand. Tournament, I'm second in chips in the SB. Chip leader is to my left. UTG shoves, folds around to me and I look down a KK. I think I'm the BB so just grab my stack of big chips (I have various stacks of smaller chips behind representing probably 10% of my total) put them in the middle and instantly table my hand. To my horror I hear a voice to my left say "call" and the chip leader who just as quickly tables his AA. There's a bit of confusion at this point but TD says hand will just plays out with cards face up. Flop is dealt, I check then BB... checks??? turn is dealt and I check and BB.... checks again???, Riveer comes a K, I say all in and BB folds.

The funny part is he was apologizing to his opponent for helping him make a good fold which reminds me when someone calls a big bet or an all-in out of turn while the action was on someone before him who was tanking, he always apologizes to the guy who was tanking for jumping ahead of him when he actually helped him greatly. He should be apologizing to the original bettor, but they never do. They always apologize to the person their out of turn action helped instead.