I once had a colleague who hated me to the point she refused to talk to me. The weird thing was I had no idea why. Even when I offered her to have an open conversation, to clarify what happened, and how can I possibly fix it, she just didn't respond. Was kinda difficult to work with her :-)
Could your manager have helped figure this out? Even if they can't change anything, it can be helpful to loop your manager in so they aren't surprised if a simmering conflict erupts down the road.
