it could be a different bug, but have you tried replicating it without running any specters?, as pinpointing the issue will be helpful if the issue ever gets looked into by the devs, also ammo mods like vigilante supplies (which i originally thought was the culprit until i tested it).
as far as my bug is concerned, it was happening long before the ammo change, but specters still used ammo afaik, they just regenerated it over time. the only difference is that before the change i could switch to operator and back and it would fix the issue temporarily, it doesnt now.
i can easily replicate the issue (incase any devs are interested i can supply a vid), and i can fix it by supplying ammo to the specters, reloading all of my weapons or resummoning my specters. the issue happens most commonly when i am using a weapon that does not use ammo like the cycron or melee.
gl