Frozen by "friendly" fire

I couldn’t find anything about this on the forum but it would be very difficult to prove and easy to just shrug off. But this has happened way too many times and also with a friend who was helping me prove out that it wasn’t my character. My Immortal WW Barbarian with unstoppable is being frozen by Sorc abilities. I don’t know which one because I don’t have a sorc but when we were proving this theory, we were in a 110 pit, just the two of us. When the sorc would use their freeze ability, I would get frozen, even when using Iron skin. When I would separate from the sorc and move away, I could do the rest of the pit without being frozen. We tried this out multiple times and it happened every time. It has never happened to me with any other group of specs, only with a sorc in the mix. I don’t know if it’s a bug but it might be worth looking into. Thank you.