Random Z plunge after an hour of running smooth?

Here’s all the info one may need:
The machine cut to the specified depth of .5mm for an hour then plunged down till the collet was in the wood making a straight diagonal path.
I have a 3018 pro and use easel to design and carve.
I just upgraded to the 20000rpm spindle (with the upgraded power supply), maybe that has something to do with it?
I check all screws and connections before every carve, nothing was loose.
I was running at 450mm feed rate, .5mm depth per pass, and a spindle speed of 14000

Any ideas on how this could’ve happened would be great. Thanks!

on a 3018 I would check the brass antibacklash device which moves the Z up and down, certain runs of these have had poor material composition and the threads that run along the lead screw stripped out very easily on certain batches of these. Also make sure to check the set screws in the stepper to lead screw coupler and the bit itself in the collet.

I wouldn’t expect this to be a cause of Easel itself without seeing all of the Easel settings and one being set incorrectly (like depth per pass for instance)…