I have a UM2 and am printing with Matterhackers 3mm PLA. My first layer seems to be consistently off. I have tried to re-calibrate the print bed and there is a little effect but not a big difference. My concern is that I seem to get 'pillowing' or what I assume to be some sort of pillowing at the top but seems to be pervasive throught the layers of the print.
Being new to 3D printing, I am happy to post whatever information would be helpful in sorting this out. Thanks in advance for helping, I do appreciate it.