You can reload even if you have full ammo with active reload

[Claymore77]

The thing with this is when you reload with the scroll wheel, the game detects that you reloaded again so you reload 2 times instead of 1

 

[Volante]

this was added in the recent big gameplay patch, i had the same scroll wheel issue with something like mcginnis wall apollo 3 and trust me you just gotta rebind it man....