Sounds like you have the Mk2 figured.
The Mk3 probably just needs a recalibration but there are a couple things worth noting:
EDIT: Also worth nothing Mike and I did a big rebuild on the extruder head and the wear components on it were replaced, with every fastener on the entire machine retorqued. So in general it's good.
I can't remember if there is PEI replacement sheets in the spare parts, I thought I ordered one but my receipts say otherwise. There is a brand new steel PEI sheet that belongs to Makerspace that is destined for the Mk2 upgrade however. That could be used if you really can't get stickage to happen.
Questions on how to use the forum? Want to learn about 3D Design or 3D printing? Please ask me!
As the title suggests. The MK2 is dark. The MK3 has bed adhesion issues. Any printer wizards out there? I'm out of practice.
Edit. I just remembered where the power switch on the MK2 is. Senior moment.