A couple UNIT things I maybe will gripe at them directly about but just watch-out-for level things so far:
1) I guess the paint maybe goes bad when unsealed? We use NMRs for our purposes, but with the trial one I got a pack of paint, have been using for famfire (when into a target etc where it doesn't matter) and zeroing and stuff. Well, last three mags I did that with I had to strip and clean the gun. They are leaking, not so much bursting like old bad paintball days, but enough the accuracy drops instantly to like 40 moa. Cannot hit a person at 10 yards reliably, that sort of bad.
(Remember, airsoft internal ballistics are more like early black powder, with blowby and stuff, not obturation).
2) I managed to get a TPAK stuck inside the magazine body (probably one that got dropped onto concrete* during a reload. When empty and I went to unload, it didn't slide out. I took the entire baseplate off and then tapped it on concrete and eventually it flew up at great speed, smacked the ceiling and broke into pieces and sprayed around the room. If anyone had been over it, maybe ER visit time. Really launched.
So on inspecting — and this may be in the manual, but still the rest of the system is idiotproof — we realized there is a procedure supported by the mechanism. When you want to change out a TPAK, release to the first step, then STOP.
Make sure the gas released and the TPAK is rattling around inside the magazine, so will come out freely and is not under any pressure. THEN release the safety clip to get the thing apart.
I should not have released the whole baseplate, even if I had to whack the thing to get it out, there's a thing to prevent it launching into space or through your eye so use it, but as I said: procedural, not enforced by the mechanism automatically.
* I avoid this still because 1) cost of the magazine if it does break 2) while heavy duty I still do not trust them not to break 3) they still have the biggest issue that airsoft gas mags have in that empty they weigh a lot still so plenty of mass to cause momentum based damage or even injury. I've seen real rifle magazines disassemble themselves if dropped during a stoppage drill, fumbled reload etc. If practicing emergency reloads, try to set it up so the mags fall on a soft ish surface. I may try to figure out how to maybe glue on rubber pads to the baseplate to alleviate this since e.g. old school Magpul won't work with the basepad mechanism.