Up to Veteran Rank 5, Crown Potions will always scale with your level. Because of that, there are certain instances below level 50 where a Crown Potion of the same level as your character may be more powerful than the lower-level crafted potions that are available. This has been the case with vendors potions since launch. However, for Veteran Ranked characters, crafted potions will always be more powerful than Crown Potions.
Crafted potion using Cloud Mist: Health 6441 Magicka and/or Stamina 5778
Tool Tip in Crown Store: Health Potion gives only health boost and no other effects, Health 5697. Magicka and Stamina 5094
I haven't actually bought one so I don't know if the tooltip is telling me what I will actually receive.
In this post it states:Up to Veteran Rank 5, Crown Potions will always scale with your level. Because of that, there are certain instances below level 50 where a Crown Potion of the same level as your character may be more powerful than the lower-level crafted potions that are available. This has been the case with vendors potions since launch. However, for Veteran Ranked characters, crafted potions will always be more powerful than Crown Potions.
If you bought a potion from the Crown Store and are seeing a higher effect than one you can craft, you may be experiencing this scaling issue.