Plumonium,
I know this is old but I suddenly started having exactly the same symptoms on my Pin Bot. I read your resolution and thought gee I didn't resolder any wires on that limit switch so how could mine possible be acting up for the same reason. But I thought hey I'll go take a look at the limit switch and damn if one of the blue/green wires wasn't broken lose!!!
So a great big thank you for helping me solve the same problem.
Alan