Your retract height in Job Setup (gear icon) | Machine is set to 8 inches — please reduce to something reasonable.
What’s happening is it’s lifting up, hitting the top, grinding against the top stop, then it thinks it’s 8" above the surface and tries to plunge that deep.
0.125 inches is a lot of plunge for a 1 inch wide endmill — please take just a bit off with each pass — see Wasteboard Plans with threads — usually when tramming one wants to take 0.1mm off with each pass, and hopefully ultimately to have taken less than 0.5mm off in total.