I discovered a tiny bug in CUP: The L85's don't accept tracer magazines.
I've already reported the bug on their issue tracker. Another bug I added (Silencer clips into UGL assembly on L85A2 UGL) already had one of the devs assigned to it within minutes of uploading,
so I'd expect them to fix most of the bugs that are currently getting reported with the next update.
Given how much testing/Q&A they apparently did for their first release, I'm not holding my breath for a super-fast patch, though
So expect L85's to get tracers with the next update, but don't expect the next update tomorrow