I had the same issue on my MMR left ramp, Bending the arm did not fix it. I had to loosen the switch and pitch it on more of a angle since the arm was not going down far enough to trip the switch even when it was bent.

That switch is very low quality.
I ended up replacing mine. It was a pain in the ass to replace, but I've not had a single problem since.

I don't remember for sure, but I think I got it from Marco.

At first, I was going to try and replace it in place, but went ahead and took the ramp and track apart. It sounds like more work, but I figured I would most likely have to go down that path eventually and just bit the bullet right from the start. There's not a lot of wire length to work with.

Take your time. Take pictures. Do yourself a favor and Lay down a white towel or piece of fabric under the area to help catch the little bolts, nuts and backer plate that you're going to drop at least once each. You'll thank yourself.

I'm posting this solution for posterity for those that just want to keep the machine working and don't have a replacement switch on hand.

This switch is extremely cheap, and the problem may be the same as the one I just fixed. Apparently the actual connectors break or come loose INSIDE the switch, so you need to create some tension with a small ziptie to secure the two legs with wires on them so they don't move (which causes the intermittent function). Works perfectly and while not a permanent solution, will keep the machine in operation while you order in a replacement switch.
switch-area (resized).jpgswitch-ziptied (resized).jpg