While otherwise a perfect fit for the Ender-5 Max, CoPrint's original mounting adapter features voids around the screw holes that don't seem to match up with any provided hardware, or with the M3 screws they provide with their kits. The nuts are able to spin within the voids, preventing them from being fully tightened, and when the nuts are placed outside the voids (on the back of the model) the amount of flex that the voids create allows the nuts to vibrate loose. After a couple of longer prints failed because of this, I opted to see what I could do to fix it.

I closed these voids and embossed an area for an M3 nut for each screw point on the back of the model, which prevents them from rotating. I've had no issues with the print head coming loose after making these changes. 

Remix shared with permission from CoPrint, with respect for their digital license. 

See attached documentation for instructions on removing the Ender 5 Max print head and installing the ChromaHead.