Homing Switch problem

Hi
I have a 6040 cnc with USB connection. I have installed, wired and setup Homing limit switches in parallel mode. i have set up Mach 3 software and when Homing CNC, all home perfectly.
But what I have noticed - the spindle moves up in Z, operates the switch in rapid movement, moves off the switch, then slowly operates the switch again and moves away. Same for X and Y. i.e operates the switch twice.
Can anyone give me a clue as to why this is happening.
thanks in advance
Nakus

The first homing is done at fast speed to save time. The second homing is done at slow speed to improve accuracy and repeatability.

great