In Frozen Bridge (Act 2 of Beneath the Frozen Earth) , the Trog Gougers use Crude Plate armor to block attacks from behind. Crude Plate is not supposed to block attacks from behind, yet it does at least some of the time. For me, it happens fairly regularly.
Possible that you're flanking rather than standing behind - only a row behind counts as behind after all. Highly unlikely I know. Try getting a screenshot and a copy of the log if it happens again.
I tried to reproduce it, and it only happened once this time. I used Charge when starting in a direct line behind my target, and ended up exactly behind him with him with him facing the other direction. Crude Plates prevented the damage. I tried using other attacks which I believe sometimes failed in the past, but they didn't fail this run, which I happened to win for the first time so I can't test again till it unlocks tomorrow.
I just used Predictable Stab while standing in the square directly behind a trog with Crude Plates. The plates blocked the damage. I think I've seen similar events 3 or 4 times now. I'm pretty confident they're not working as intended.
This would be weird since it has been extensively tested before. I'm definitely not saying that anyone is lying but i experienced no blocks from behind while doing those adventures.
