I've been having this problem for a while now but I haven't seen anyone else post a bug report for it. When I'm fighting giants, any giants, 80% of the time I do NO damage. It takes me nearly two days to kill deerclops even though I'm dodging his attacks nearly every time, yet I still get killed. Very frustrating. At first I thought it might be my mods but I tried it without them and it still happened. I don't know what's going on but it feel really bad to kite an enemy nearly perfectly but still get killed because it "eventually" does enough damage to kill me.
Someone please tell me you're having this bug too so I don't think I'm crazy.
Fight a giant.