Suddenly my Gen 5 has an out-of-control build plate. When it rises to print or level, it doesn't stop. The plate hits the extruder nozzle, makes a terrible clicking noise as it keeps trying to rise, and then I cancel the print. At that point, the plate won't lower like it usually does. I've turned the Makerbot off and on. I've manually lowering it, but that doesn't prevent it from happening again.

My software and firmware is up to date. Any ideas?