Extremely unusual Party NL 50 folds - software glitch??

[BlueBear]

The following hand history is probably the strangest hand I have ever played. Two players VOLUNTARILY folding onto my bust draw! There are no disconnections but the fact that two players may have clicked the auto-fold button is very very unusual... or perhaps is this a case of a server glitch?

Party Poker No-Limit Hold'em, $1 BB (6 max, 5 handed) converter

SB ($30.15)
BB ($60.7)
UTG ($49.1)
MP ($44.1)
Hero ($151.4)

Preflop: Hero is Button with 3[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/heart.gif[/img].
<font color="#666666">1 fold</font>, MP calls $1, Hero calls $1, SB completes, BB checks.

Flop: ($4) 5[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/spade.gif[/img], 6[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, BB checks, MP checks, <font color="#CC3333">Hero bets $3</font>, <font color="#CC3333">SB raises to $6</font>, BB folds, MP calls $6, Hero calls $3.

Turn: ($22) 6[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, MP checks, Hero checks.

River: ($22) A[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
SB folds, MP folds. &lt;----------- WTH is going on here???

Final Pot: $22

Results below:
Hero has 3h 4h (two pair, aces and sixes).
Outcome: Hero wins $22.