Alchemy by zero (The Elder Scrolls 5: Skyrim)

Game version 1.9.32.0.8 LE. Clean, no mods.
Alchemy pumped at 100 LVL and explored all the perks, wearing 4 items with 25% increased alchemy, and when you try to create a potion effect such as if I have a LVL 15 without things. 1 set of armour was not displayed in the active effects, but when made new, all the effects displayed from one subject and in the end the potion with the increase of the skill by 4%. Tried to make alchemy legendary and pump again. It did not help. Tried on an early save. There all work properly.