PLO $50 - Weird top-bottom 2 pair, donked when straight card hit

[YKMM]

Villain is an extremely loose and somewhat passive and straightforward postflop
54/14.3/1.80 (32). No other history or reads. My plan was to pot a blank on the turn. However, his turn play surprised me and I read the donk bet as a made straight. Any comments on my play?

PokerStars Pot-Limit Omaha High, $0.50 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

MP ($114.35)
CO ($53.45)
Hero ($59.45)
SB ($49.50)
BB ($85.80)
UTG ($9)

Preflop: Hero is Button with 6[img]/images/graemlins/diamond.gif[/img], Q[img]/images/graemlins/club.gif[/img], J[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/club.gif[/img].
UTG calls $0.50, MP calls $0.50, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises to $2.75</font>, SB calls $2.50, <font color="#666666">1 fold</font>, UTG calls $2.25, MP folds.

Flop: ($9.25) A[img]/images/graemlins/diamond.gif[/img], 4[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, <font color="#CC3333">UTG bets $2</font>, <font color="#CC3333">Hero raises to $14.8</font>, SB calls $14.80, UTG calls $4.25 (All-In).

Turn: ($45.10) 7[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players, 1 all-in)</font>
<font color="#CC3333">SB bets $17</font>, Hero calls $17.

River: ($79.10) 2[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players, 1 all-in)</font>
<font color="#CC3333">SB bets $14.95 (All-In)</font>, Hero folds.

Final Pot: $64.15