this is why its called the 2nd nut flush and was one of the first hands I posted when I was at 2NL
PokerStars No-Limit Hold'em, $0.02 BB (9 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

Button ($2.12)
SB ($4.96)
BB ($4.84)
UTG ($2.06)
UTG+1 ($5)
Hero (MP1) ($2.63)
MP2 ($1.54)
MP3 ($2.83)
CO ($3.76)

Preflop: Hero is MP1 with K, J
UTG calls $0.02, 1 fold, Hero bets $0.04, 3 folds, Button raises to $0.14, 1 fold, BB calls $0.12, UTG calls $0.12, Hero calls $0.10

Flop: ($0.57) 2, 7, 8 (4 players)
BB checks, UTG checks, Hero bets $0.54, Button raises to $1.98 (All-In), BB calls $1.98, 1 fold, Hero raises to $2.49 (All-In), BB calls $0.51

Turn: ($7.53) J (3 players, 2 all-in)

River: ($7.53) 7 (3 players, 2 all-in)

Total pot: $7.53 | Rake: $0.35

Results:
Button mucked Q, Q (two pair, Queens and sevens).
BB had A, 3 (flush, Ace high).
Hero mucked K, J (flush, King high).
Outcome: BB won $7.18