Pretty low priority: I have noticed a new trend in potion brewing. Brewed potions suddenly don't stack with eachother, automatically. I've only had this problem since the new brewing system cam out, yesterday. It occurs with Invisibility and Cure Serious Wounds, but I have to add I didn't test it with other potions yet.

This isn't actually an issue. Brewed potions are marked "stolen" so they can't be sold to NPCs, and will stack with each other (but not potions that aren't marked stolen).