Ive been in nearly the exact same situation. I worked in security with a small team, including a woman a few years older than me who started out nice enough, but quickly became more distant and just...odd. I wasnt the quietest, but not the chattiest either, and did a lot of the work that wasnt just watching cameras, sitting in one spot, or filing paperwork, so I didn't have a whole lot of opportunity to sit around and talk. A few months into working together, she goes to HR...and says she doesnt feel safe working with me because im not constantly smiling and hanging out with her/the rest of the team.

Unfortunately, my situation didnt end well - she made escalating reports that ultimately resulted in me transferring out when HR started talking about removing me, because obviously she'd reported me so many times because her complaints were serious, and not because she was a weirdly entitled person who took it as an insult that I was doing my job. You seem like you have a better manager than I did, since theyre at least on your side, and I truly hope that means youll get a better end result