Seen that somewhere as the
Wizard's Backpack or something like that.
I think at death or some other exceptional event (like a Dispel Magic

), all items should fall out, maybe with that fire damage, but surely with falling damage (mostly very small, but potions don't need much to break).
Now some really weird thought that occured to me:
Hah, extra-dimensional. There must be something even THERE. And why is there nothing, if we can store our crap there? Maybe nothing, like vacuum? But vacuum is not just everywhere, it is for example in... in space!
So you actually deposit all your stuff somewhere in another-dimension's space. Of course it does not just fly away, it is held in a magical force-field. (Do not want to speculate about the physical relations between two dimensions). We can theorise that force-field can hold even air (might have really dangerous consequences otherwise), so potions and bottles do not explode from pressure.
Now, what is the consequence of storing items in space? Air OK... there is
one more thing: radiation. What if all items you pull back are irradiated? May be really bad, especially the potions or food you want to consume at some point...
Think about it.