Yup, chances are you have a cold solder joint and not putting all the screws back in/not tightening them all the way relieved some stress on the PCB and allowed the broken solder joint to make contact.
Most modern electronics are now RoHS compliant, which means among other things, the solder has no lead in it... This leads to flow issues, worse tin whiskers, etc, etc.
I wouldn't send the part back because Murphy will show up in its place, for sure
