Don't know about questions, but there are couple of answers I have learned to be serious red flags: 1. Yes, I understand. (with no further elaboration or clarifying questions) 2. It's okay/good/going well (again, with no further elaboration when asking how something is going/set up etc) First one typically translates to something between "I have a completely unfounded illusion of understanding" and "I have no clue bu…
I do also ask questions without hesitation when needed (to the point where it starts to irritate non-developers), but saying "Yes, I understand" or "it's going well" when I do understand and when it is going well is not a red flag.