I have experienced the exact same problem.  However targeting problems are not limited to the nurglings - I find that there are targeting issues whenever there is a change in platform level.  For example, if I am kiting enemies up or down a ramp I cannot target them until I reach the next level (up or down) and they either reach the same level that I am on or at least get close to the same level.  This makes combat very difficult for a character with a ranged weapon.

Platform maps also cause pathing problems all the time.  Unless I rotate my camera view to be behind my character I can find myself in a situation where the game will have trouble understanding where I want to go or not move me in the worst case scenario.  This is not good since there can be times where you are running from a mob and you don't have time to reorient your camera view.  Today I also fell through a platform, but luckily I was able to retrace my path and it returned me back to the original platform (from an animation perspective it was almost like my character was on an escalator - she walked a short distance and then "slid" upwards back to the original platform).