This is a know problem unfortunately. I just recently started experiencing it out of the blue back on the last 2018CC version and it is still plaguing me on the PP 13.0.2 version as well. It has to do with your monitor scaling in your display settings in Windows 10. I have a 32″ UHD monitor 3840×2160 (and 2-2560×1440 monitors on each side)and when I have my scaling set to 125% (my preferred setting) the bounding boxes do not show. I discovered this week that if I don’t maximize my PP window on that monitor, (“ctrl” +”\” shortcut) that the bounding boxes come back, so that is my workaround for the moment. I use the shortcut to make the window slightly smaller, do my graphic and then maximize the window again when the graphic is completed.
If my display setting is set at 100% (then the text is too small for my eyes) or 150% (everything is too big and can’t get enough of the interface on the screen) the bounding boxes come back.
Here’s a link to a thread on the Adobe support forums discussing the problem in more detail:
https://forums.adobe.com/message/10848612#10848612
Hope this helps,
Rob