Flaskmaster + Grenade Belt glitch

So one of the abilities of the Flaskmaster passive perk (Tempest Specialisation) is supposed to provide an extra grenade when you equip a grenade (4 instead of 3 grenades). The Grenade Belt provides a similar effect (1 or more extra grenades depending on the rarity of the belt).

Now I can buy the extra grenades just fine and carry them around fine IF I equip them in the field to the desired character who is currently in my party. However if I buy the extra grenade at Skyhold, switch characters, or fast travel, the extra grenade disappears and the Crafting material(s) have been wasted.

I first noted the glitch early on in the game after giving a grenade belt to Varric but I just kind of ignored it. It's becomes a much bigger annoyance now that I've unlocked the Flaskmaster perk for Sera though. If this is an intended effect then I'd like to say it's a stupid one.

Not sure if something similar happens with the Potion or Tonic Belts - not tested it and I don't particularly care to.

If is the wrong place for me to be posting this, then please leave a reply with the correct forum for me to post it too. I've not seen anyone else talking about this glitch/terrible mechanic yet.