Found out, that the normal PDF-Printer for Windows has resource leaks.
It seems that a workaround was implemented by terminating the process and automatic restart after several PDF-prints.
Disadvantage is that the user-interface pops-up again every time the process is restarted.
Better solution would be to solve the resource leak: Here a hint for the developers: The resource leak can be observed by task manager if you display the "handles" column. So it's some kind of system handles like registry handles or something like that.
Appreciate any response about that.