...I don't even talk to this person, we work in a shared workspace, I have zero interest in her, and she's usually at least 20 to 50 meters away. She started ghosting me a few months ago for some unknown reason, I've tried to show professional courtesy to this person by greeting her but she's always skulking around, sometimes when I run into her it would be 2 in the afternoon. I'm not comfortable standing near her or without witness. Now I got a warning from the department manager for this "staring" bullshit, and apparently if she complains again there will be an HR investigation, and one of her buddies is willing to commit perjury because according to the manager "somebody else also noticed". Now it's 2 vs 1. Any advice what I should do? Thanks!