Throw your switches away
Seriously though its either noise (which I doubt) or your switches dont open very well. What is happeneing is Mach homes, the switch opens and Mach reverses. But because the switch isnt opening correctly Mach sees it closing again and stops the reversing but then it opens again and Mach sees that limits are active so wont continue withthe homing.
Best thing to do is wire up an on/Off toggle switch and keep your Ports and Pins set up the same way, have the toggle closed, do a home, open the toggle and Mach should reverse. Close the toggle and Mach should start the next axis etc etc.
If this works correctly then you need to look either at just thaat one switch or all of them and see if either your trigger is not opening them enough or if they are just poor switches.
Hood