Granted: microlimits. But I've played 40K hands at these limits and haven't seen this before (granted, maybe some others have called preflop with trips and just didn't make it to showdown):
PokerStars Pot-Limit Omaha/8, $0.25 BB (6 handed)
Hand History Converter Tool from
FlopTurnRiver.com (Format: 2+2 Forums)
SB ($24.80)
BB ($11.65)
Hero ($22.30)
MP ($4.80)
CO ($20.45)
Button ($9.65)
Preflop: Hero is UTG with 2[img]/images/graemlins/spade.gif[/img], 3[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/diamond.gif[/img], 7[img]/images/graemlins/spade.gif[/img].
<font color="#CC3333">Hero raises to $0.85</font>, <font color="#666666">
2 folds</font>, Button calls $0.85, <font color="#666666">
1 fold</font>, BB calls $0.60.
Flop: ($2.65) 9[img]/images/graemlins/spade.gif[/img], 2[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(3 players)</font>
BB checks, <font color="#CC3333">Hero bets $2.55</font>, Button calls $2.55, BB folds.
Turn: ($7.75) 7[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $7.4</font>, Button calls $6.25 (All-In).
River: ($21.40) T[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players, 1 all-in)</font>
Final Pot: $21.40
Results in white below: <font color="#FFFFFF">
Hero has 2s 3h Ad 7s (Low: 7, 5, 3, 2, A | High: two pair, sevens and twos).
Button has 3c 5s 5d 5c (High: three of a kind, fives).
Outcome: Hero wins $11.27. Button wins $10.12. </font>