+6 Grenade Capacity affix for Blast Master class mod bugged

So I bought all the grenade SDUs for Moze, and got 11 max grenade count. I found the Blast Master legendary class mod with the +6 grenade capacity affix, but it only puts me to 16 grenades rather than 17. The SDU purchase menu with Marcus shows 16/16, so I presume it’s some kind of hard limit, but then the Marcus vendor machines act as though I am missing 1 grenade by letting me purchase grenades as though I’m under my max capacity, but when I do purchase one my grenade count stays at 16. The grenade ammo purchase option then stays able to be purchased, letting me effectively pay $330 for no grenade over and over.

Is this an issue anyone else has seen at all?

I haven’t checked the count, but can confirm that gear that extends one’s grenade count will make the vending machine perpetually think I’m short of grenades.