PLA on satin sheet -- marginal adhesion?  

PLA on satin sheet -- marginal adhesion?

Six months into using my Core One, I am generally happy with the reliability and print quality. (Having resigned to the VFAs, which are not going away even with the latest belt tuning and slicer profiles.) "Start the print job, walk away, come back to a good result" is the norm.

But sporadically I get failed prints because the object is not adhering to the build plate. This can be a curled-up corner which results in distorted models if I am lucky, or a crashed nozzle when things go badly. Small objects may even come loose entirely. It has typically (only?) happened with PLA on the satin sheet, in different locations on the sheet.

I do my best to keep the sheet smudge-free, and wash it with dishwashing soap and warm water occasionally. I have not played with the heatbed temperature so far but always used the slicer defaults -- because the failures are too sporadic, it's difficult to do systematic optimization.

My question: Is PLA adhesion to the satin build sheet known to be a bit weak? Do I need to clean the sheet differently or more often, or is it recommended to increase the bed temperature? Or is the weak adhesion a sign that something might be off in my Core One, e.g. a deviation in the measured bed temperature or a more-uneven-than-usual temperature distribution across the bed?

(PrusaSlicer does not have a setting for the type of build plate, where it adjusts first layer height or temperature, right? Or have I overlooked something all the time?)

Thanks! Jürgen