There are several cases when the footprint becomes slightly larger.
@Julius L. I have not adjusted any thresholds. It’s a fairly new installation with none of the adjustments you mentioned.
We had the same issues with Nginx. The root-cause was that Nginx has too many workers. After reducing the workers to 1 the memory overhead became a lot less.
Unfortunately we don’t have the same luxury with PHP-FPM.
I will keep monitoring it over the next week and report back.