I cannot say that this has always been the case. I can say that I've noticed JPEGs I create with PP all have a padlock symbol over their icons. Via folder Properties, I can manually add a new "Everyone" group/user and make this disappear, but what a hassle that is.
I'm not certain this even matters, because I do not appear to be handicapped in any way, perhaps because I'm the ADMINISTRATOR and only user of this computer—I don't know. Maybe it could be a problem if someone else tried to use one of my JPEGs.
Question is, could PP be setting permissions for exports in such a way that they are born with these padlocks and permissions for SYSTEM and the system administrator?
Maybe it's a stupid Windows thing?
I should add I see the same padlocks over icons for PNGs I create, but not PDFs.