Cutting curved sections does not work well (not cut all the way through)

In general GRBL implementations will reduce power when decelerating/accelerating as what occurs in the change of direction in a corner.
The amount of reduction is directly affected by the perceived scale of speed reduction.
I suspect 2 potential things happening here:

1. Your machine is reducing speed (and thus power) considerably due to your speed settings. You could try reducing your initial speed to see if this goes away.

2. This could be a firmware bug and the implementation from xTool is simply over-reducing power during deceleration. xTool implementations have many similar firmware bugs so wouldn’t surprise me if this were the case.