I think this is down to being nervous for a large part. Maybe you could have noticed some of these red flags when you were interviewing at the company. But you'

I think this is down to being nervous for a large part. Maybe you could have noticed some of these red flags when you were interviewing at the company. But you're in a new environment, with new people, being bombarded with questions. Sometimes you're there because your current job is a giant shitstorm you want to walk away from. It's easy to miss things in that state. That goes both ways, of course. When I'm hiring I sometimes dimiss red flags because I think "they're just nervous, they're not really this dumb". But sometimes they are.