casino says my blackjack bets looked like “structured wagering” after i used same stake all night

so last friday i ran a basic flat bet strategy for like five hours straight - literally same bet size every hand, barely changed it at all. now support says my “consistent wagering patterns” flagged some system, and they’re calling it “structured wagering” and reviewing my session before processing my cashout. haven’t been accused of this before. i thought flat betting was supposed to be one of the lowest-profile ways to play, so not sure what gives.

i usually mix it up more in roulette or slots but i was focused on sticking to a plan for blackjack this time. obviously i didn’t hit any promos or abuse anything, just standard base bets and a few doubles/splits, nothing maxed out. not even counting cards, just playing by the book. anyone seen a legit reason a casino would get twitchy over that? wondering if i’m missing some angle or just unlucky with the review.