CDJ2000 Nexus 2 Bitcrush sound

Ok I read the entire thread from 2017 about this issue so I've seen that it is still unsolved, I'm starting this up again because I've recently had this issue with a unit that belongs to the club I work at. I will try to add more info and theories to the pot.

We were running 4x CDJ2000 nxs2 and a DJM900 nxs2 all connected with ethernet. 
The CDJs were all connected to mixer through digital connection.
The issue happened on the CDJ which the source USB was plugged into, although not sure it would make a difference.
The same USB source played fine on other CDJs which were linked. This happened mid set, DJ didn't have second USB so he played the rest of his set with the bit crush sound on one deck, happened every song on that CDJ after it started.
I brought the CDJ home and connected it to the same mixer in the same channel and played for close to 3 hours without having any issue.

The only other time I've personally dealt with this was with a different CDJ which had been spilled on, there were plenty of other problems happening like menu buttons triggering constantly so at the time the bit crush sound kind of seemed related to the spill. It also weirdly only affected the right channel at that time.

This time however the CDJ is clean and used regularly at the club. I've even opened up the unit to check for any spills inside and it was clean and seemed to be physically undamaged.

SO my theory is that it's an environmental issue such as over heating or possibly dirty power. Similar to when a DJs laptop is overheating while using a controller, there are bit drops which happen. it sounds different but it could explain why it's difficult to reproduce. have the engineers tried running the cdj in a hot room?