arf these are bad news
If connectors are like some HE-10 connectors, unplug them and try to pressure them gently with tool, of course protect the plastic part to avoid the tool to crush them, maybe they were fast mounted with not enough pressure ?
if soldered check them too but as you speak of PIC, you are familiar with electronics so i won't explain you what to check
What could i say more, in then end if everything fails, maybe minicom could help enter in deep with serial ports to watch what is going on.