I had a coworker like that. I assume she had BPD but all she ever said at work was that she had addiction issues. But she’d text me in the middle of the night talking about how she was S. But I’d respond back and she’d never answer. Then the next day at work I’d ask if she was ok and she would smile and say “yeah I just had a moment.” She would never respond to my texts which were mostly work related. Then she texted and said that her mom died and just stopped showing up to work. Her mom did not die by the way. It was a lie. Her mom is all over her Facebook. I never told work what really happened because I didn’t feel like throwing her under the bus. I just stopped communicating with her because I don’t want to associate myself with those types of people. I’m still Facebook friends with her though. After I posted a new profile picture during the winter she sent me a PM saying I looked great and some other BS. I answered her and got no reply. Typical.