We have an issue where our printer, since pretty much day 1, will print OK for a while, then it will eject the bowden tube out of the extruder. I can put it back in and give it a good pull and it feel secure and it will print several prints and do it again. We are using Ultimaker brand PLA, printing at 220 degrees. I have tried emailing Ultimaker for support, but have gotten nothing from them yet. Has anyone had this issue and if so, how did you resolve it?