1) Create a unit and an arsenal box.
2) Add the following items to the Virtual Arsenal:
Magazines: ["30Rnd_65x39_caseless_mag", "30Rnd_65x39_caseless_mag_Tracer"]
Items: ["optic_Arco", "acc_pointer_IR", "muzzle_snds_H"]
3) Remove EVERYTHING from the unit and then give them the "arifle_MX_RCO_pointer_snds_F"
4) Have the unit open arsenal, and save their loadout (with the "arifle_MX_RCO_pointer_snds_F" still selected)
5) Leave arsenal and re-open.
6) Attempt to load the saved loadout from (4).
Notice that the saved loadout is unloadable even though all the required items for "arifle_MX_RCO_pointer_snds_F" are present (the rifle, ammunition and accessories).
If you continue on:
7) Remove the weapon from the player in the Virtual Arsenal
8) Equip the MX rifle along with the optics, pointer, and silencer (creating the same rifle loadout as arifle_MX_RCO_pointer_snds_F)
9) Save this loadout under a different name in the Virtual Arsenal
10) Go to the 'Load' menu
Notice that now the loadout from (9) can be loaded successfully, but the loadout from (4) is still unloadable.
This behaviour is extremely confusing to users (since the box contains all of the required items) and makes it appear that their loadouts aren't saved correctly or that Arsenal is malfunctioning.
Easy to repro in attached example mission with provided loadout. Simply walk to arsenal box, save current loadout and try to reload. If you reconstruct the weapon with items from the box it suddenly becomes loadable.