Sam10

I have been having problems with my Ultimaker 3 as of lately. When starting a build the print cores do their usual heating up, but lately PC has been extruding during that heating up then leaves a big glob on the tip of the print core. This is problematic because it does not allow for further material to extrude, and also drags across the build that the TPU 95A printed out and pulls it up and destroys it. I have cleaned the feeder and the print core following the instructions on the website and nothing changed. Any help would be greatly appreciated, and thank you in advance.