by cncdrive » Mon Dec 07, 2020 7:34 am
The M5 command is aszncronous to the motion which means that when there is an M5 command then the controller waits for the motion to end emptying the motion buffer and then executing the M5 command and then continuing to execute the g/code program.
So, it cannot be the lookahead problem.
I don!t remember that anybody reported any issues with the M3^M5 switching with any versions of the UCCNC, so I doubt that it is a software problem.