Depends on how the rest of your CV looks like. If you just have short term jobs, sure it’s a red flag. If you have one ones in a while, everyone will understand that it just didn’t work out.
I've got two <1y permanent jobs in a row on my CV - first one was running out of money and I quit to save them a salary (I didn't believe in the holy grail pivot or new tech lead - company folded 2 months later anyway); second one "let me go" after they got a new tech lead that didn't agree with my approach. Neither is a red flag, both are just bad timing / luck.