Infinite Black Soul Gems, Anyone else get this? Bug? Options

[Olav]

I've only created 5 black soul gems through the altars. However, I think I have about 30 now, and I haven't made any more. When I kill vampires or Xivilais or other creatures that qualifies as grand souls with Umbra, I get a new filled black soul gem from out of nowhere. Is this supposed to happen, or is it a bug? It doesn't happen every time, but most of the times.

Also I think this happens with greater soul gems as well.

On a similar note, the enchanted chest does not produce ingredients anymore. It did the first time, but not anymore. I have a flax seed in it, btw. Not sure if this is relevant, but it can somehow seem like instead of giving me extra ingredients, the game gives me extra soul gems...

[Olav]

Yes I have those.

I've noticed a pattern of some sort: Whenever I enter a new area I can trap 2 or 3 souls even if I have no free soul gems, and then I get the message 'you do not have any soul gems large enough...' etc.

So I always try to trap 2-3 dremoras or some grand souls when I first enter a new area.

Obviously this is some kind of bug, but I see it is very handy as that Hatred of Souls bow is really eating soul gems...