Just a really bad suckout or .......?

[dreamcircus]

$3/$6 ring game 6-handed, BB $4000, Hero UTG $1900, Villain $700, Big Stack $5000

HOLE CARDS: KcTd
Hero UTG call, 2 folds, Villain call, Big Stack calls

FLOP($27): 7c6c8c
BB checks, Hero checks, Villain checks, Big Stack checks

TURN($27): 7c6c8c9h
BB bets $20, Hero raises to $60, Villain raises to $150, Big Stack folds, BB folds, Hero raises to $250, Villain raises to $500, Hero is all in, Villain calls

RIVER($1435): 7c6c8c9h9c

Hero (KcTd)
Villains(KdTc) wins $1435 with straight flush

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Is this just a really unlucky bad beat? I think it is, but it's not a small pot and it bothered me. Villain and Big Stack had been very aggressive for the past 30min. Was pretty sure someone would raise flop but no one did. I don't know what I could've done any different to blow him off the hand on the turn? Didn't feel I needed to as I wasn't afraid of him drawing to river but what came shocked me..