UCCNC and THC re-zeros tool hight randomly

[specnaz]

So I've been cutting with this plasma for a while and finally got the THC to work too, now what happens at the end of some random cut the torch dives down despite program telling it to go to 0.2" to Pierce height and is it does dive down it sets new Z (say if its in a cutout hole the tip jams itself in and rezeros itself there) Not sure why or how would it be possible to rezero itself with no command to do so?