Why would a coworker who doesnt even talk to you, send you a request on LinkedIn?

We used to be on the same team. She was very distant.
I'm on a new team now.

I saw her in the hall. She was standing in the doorway of a room, and was looking down the hall at me.

I had just come in the building, and she was looking. I was gonna just say hi but as I got close, she quickly went into that room.

weirdos🙄🤷‍♀️