I can only throw one grenade when it says I have 2

Games Halo 5: Guardians
1

every time I spawn in slayer or arena, It says I have 2 grenades, as always, I throw one and then the grenade count drops to zero!!

wtf lol

proof: https://vid.me/nMdT

2

Weeeeeird, haven’t seen that one before, no idea mate sorry