I just purchased my k1 max last week. I was able to get three decent prints out of it but now the locking lever on the extruder will not stay locked. I have even set the print speed down to 100mm/sec and it still does this. I have three successful prints and Dozens of failed prints. I have removed the extruder and checked the everything. It looks like I have the updated internals on the extruder. I have checked for clear hot end and it seems good. Any advice? Or do I have a dud?