Max ammo lowered after reloading

I am playing Borderlands: The Pre-Sequel on PS4.

When I reload a weapon, the max ammo counter lowers. For example, if my max ammo is 999 and I shoot a bullet, after reloading the max ammo is now 997. Each time I reload, it lowers. I have restarted the game and the issue persists. I have removed all shields, Oz, and class mods and still have the issue. This happens with all weapons that I equip. I have removed and equipped a variety of weapons.