I really don’t know whats happening. Especially with the Over and Underextruding… Heck the Bottom Left pic shows both happening basically right next to eachother… whats going on?
(The Printed Model in the pic is just the Entire First layer and buildplate printed in. Letting it Run a Third time now to see if the Patterns stay the same)
My first impression from the adhesion issue (which doesn’t appear to be the main issue of this post) is that you may need to clean your build plate. But considering it was relatively good as it is, I assume you did and the few spots may just be accidental touches to the surface. In either case, their guide is here: https://wiki.bambulab.com/en/filament-acc/acc/pei-plate-clean-guide
As for the extrusion issue - considering the apparent randomness of it my guess would be either an issue with the filament or a partial clog.
I had this happen on my p1s with a roll of Inland pla, but not with a roll of their pla +, I also noticed my nozzle was worn (who knew that after 850 hours you should probably replace it). Haven’t gone back to the normal pla yet, but those might be things to look at?
It can’t be filament or a clog. The length of each diagonal extrusion path changes, so it is impossible for that to align perfectly with a pattern on the build plate like this.
It could be contamination of the build plate, or an issue with sensor noise related to however the the bu checks for bed height. Depending on method of bed height sensing, it could also be related to bed leveling versus the sensor mapping resolution. Again, this is just a general hardware assessment. I don’t know the specifics of how this machine works and have no interest in learning anything about it. Hardware wise these are the issues I can think of. It also looks like a high first layer to me, with an additional issue too.