malfunction during homing

Hi guys.
I have a small malfunction that I cannot understand, also because everything works regularly.

During homing, the X axis moves smoothly at HOME_SEARCH_VEL, speed.

The Y axis, on the other hand, moves in more or less long jerks, sometimes covering 1 centimeter, another 5-6 centimeters.
I set the same data on the two axes in the .ini file.

The same with the Z axis with LinuxCNC 2.5.0.

By installing 2.7.0 it only happens with the Y axis.

I did a test by inverting the parallel output pins in the .HAL file and at this point it was the X axis that was jerking, so it's really a linuxCNC software problem and not the motor drivers.

Thank you in advance.
Roberto