Awkward

I interviewed for a job and one of the panelists ended up being someone I knew. We were in a very small, very personal cohort together for our graduate studies not too long ago. I waited for them to mention knowing me, maybe a hello or something , and they didn't. When I asked my interview questions to the panel, this person seemed to respond condescendingly. I've asked the manager for feedback, to which he gladly said he would call me - I almost want to ask if that person mentioned knowing me. It felt less professional and more passive aggressive. I'm a little worried they may have had some sort of bias against me that hurt my chances getting the job, not that I would want to work where I'm not wanted anyway. I'm sure I'm just reading into things too much, but has this happened to anyone else? Is this expected behavior from a panelist that knows you? Would you mention it to the hiring manager?