I know the problem, I just don’t know the solution. Everything fails where the heavy infil changes to a wall section. It’s a combination of the head catching on plastic, the servos skipping as a result. I’ve got the servos running at 200F (93C) which is hotter than I’d like…I’ve got Z-lift, but there are still some movements that are fast enough to catch on things, that Z-lift doesn’t seem to come into play (I’m not hearing the height change before movement.) I figure rapid movement is causing the effector to twist during movement, causing the nozzle to dip and catch.
What hot end are you using? And is it the original nozzle? Depending on the nozzle type it may be dragging due to not being perpendicular to the bed. Check that and and make sure the hot end is plumb. If not make it that way then level the bed. If everything travels in its appropriate plane and the hole in the nozzle terminates on the the same plane (perpendicular to the bed)as the metal around it it shouldn’t drag. That is unless x and/or y are also moving in z due slop or racking forces.
Are you overextruding by chance? There shouldn’t be so much plastic that there are grooves in it from travel.
It’s a delta, so all of the planes have a coordinate transform in them. 
Did you put rubber bands or springs on your delta arms to keep them stable? That will reduce the chance of the delta wagging the hot end around like a tail and therefore let you keep the jerk settings up. My delta arms are a bit weeks and the u-mounts have too much play on them…thanks to me…so I need the tension. You might need it too.
No, but I’ll give it a shot.
@Mike_Miller please note that you should not use too strong of rubber bands or have them far from the u joints. Either one would cause a calibration issue. Rubber bands may crap out on you with time too.
@Mike_Miller oh. What about the nozzle’s tip? Is it physically parallel to the bed in all positions?
It’s very close, if you’re using .2 mm layers, its probably about .1 mm actual on the z tower and .25 mm on the Y with X somewhere in the middle. The effector plate has had some problems and I’ve got a replacement printed, I’ll look for light springs when I replace it…probably from Napa.