Your gut is a good first alarm. Their pattern over time is the full report.

Instinct is fast and imprecise, which makes it a useful warning and a poor conclusion. It registers something off before you can name it, and it also fires on people who merely remind you of someone else. Treating the first feeling as proof is how you end up unfair; ignoring it entirely is how you end up surprised.

Use the feeling as an instruction to look closer, not as a verdict. Watch what the person actually does over a few weeks, especially when it costs them something. If the behavior matches the alarm you have a finding; if not, you learned something about your own triggers.