Now with 25% moar OP! [the UBGL had a 2 shot magazine as well... and all the shots do damage, at least for the UBGL =P] I think it's caused by using a warp terminal when you're reloading?
I've seen this bug too. I think indeed it could be related to using warp-terminals yes, because I managed to get something like 41 bullets in one of my vanu weapons.
You ever seen that glitch where it looks like the guy is just constantly shooting and never reloading? Just, constantly shooting and never reloading. That's what every TR grows up wanting to be.
It'd be nice to explain to the less enlightened that the weapon they're looking at, possibly the Trac 5, has a 40 bullet mag and in the pic it shows 50. This has happened to me too sometimes on my Gauss S showing anywhere from 78 to 90 bullets instead of the 75 it should. Personally I prefer to empty the mag and reload instead of risking to find myself shooting blanks in a firefight.
the only advantage TR really has in it's mag capacities is in it's ARs and some Carbines. I miss the extra 10 bullets from a Cycler or Cycler-S when I'm using a Corvus or Gauss Rifle