Dreadnought Paragon issues - at-wills not hitting mobs

cacaum

Savage Slash, AND Reave the dps fighter at-wills, NEVER hits some smaller mobs if they are at the same horizontal plane as me or in a lower position. All other attacks will hit normally. The attack will clip right through the target, without touching it. The animation is properly performed, but no damage at all. So far I found the issue with these mobs:

1. Spiders (the little ones we find for the potion quest right at the undermountain campaign start)
   
2. Cave crabs found at the Slimy Alcove area
   
3. Myconids - for those the issue is very rare
   
4. Spitting spiders on Wyllowwood
   
5. Blade spiders, some times, on Wyllowwood if they are in a different horizontal position
   

I'll update the list, should I find more 'immune' mobs.