So I used the "mod showcase" to mess around
Came upon the "VX Custom Class"
started messing around and noted that putting a ion cannon in the left slot causes the arm to despawn
went back to it today and messed around with other slots
Noticed a pattern, it appears the vanilla weapons with a "charge up" effect such as the Ion Cannon, IR Pulse laser and Railguns all cause this ?
Slotting in certain other weapons fixes it and respawns the arm
Further, the right arm has somthing similar going on where weapons with a "spinning barrel" animation cause the weapon to spawn on top of the mech and not have it use the arm to fire
Weird stuff
Thanks for the report!
the arm disappears when you slot in a weapon with no cooldown/chargedown (such as ion cannon) since the recoil anim is tied to that. im guessing the sprite probably ends up floating around at some Y value offscreen. I fixed this for the right arm but forgot to check for it on the left sooo i'll do that rn.
I've never seen and haven't been able to repro the rotary weapon bug though, unless what you were seeing was in the refit screen only (since they do show up there, but don't appear in actual combat)
Anyway, ill put out a fix soon alongside some other changes, I just need to squash a bug with WINGCOMs promo system first.