I suspect this might be connected to September update, as today fonts on the panes became jagged as per print screen. Yesterday I was still on August update. I am using second display and when PBI Desktop window is moved to primary all is fine.
I am unable to correct it through clear type font options on Windows 10 for secondary display and other apps seem not affected. In August update all looked OK and other than on panes all fonts look OK even on second display.