Weapon attachments dont work until you unequip and re-equip them

Noticed a bug when a buddy and myself were playing in co-op.
Anytime we would load into the game and choose a starter character, our weapons wouldnt recognize the attachments that were equipped.
We would have to respawn, go to the weapon, unequip the attachments and re-equip them for it to work.
Before the match if we do the same thing then it works.
Only works if we unequip and re-equip.  
Seems pretty annoying especially if you accidently forget and load in just to have to lose a life over a respawn.