I'm working on a project that just requires a 40 pin PIC; nothing fancy, any 40 pin will do. I have an old batch of PIC18F26K22's from a project years ago; brand new, bought from Digi-Key, still in the shipping tube. I found the pins couldn't deliver clean digital outputs; a LOW still had almost a volt, while a HIGH was barely over 4 volts (at 5 volts VDD). Switched to a K40 and everything switched clean. Maybe older stock somehow has issues, and with the electronics shortages, I've been told sellers are dusting off older Revision parts and selling them. The possibilities are endless, all things considered.