Already an iOS user into Adventure Pack 3. Bought Steam base version, added on the free Epic and Legendary Card DLC. Installed, then fired up the game and device linked. Game restarted.
I do not have access to the Legendary and Epic rarity Treasure DLC though it says it has been installed. Only my previous card unlocks.
Example: Per the Steam Epic and Legendary DLC description I should have Favor of Desna/B/Epic. In my collection it shows up as missing when I got to the Filter Treasure option under blessings along with Favor of Erastil, Favor of Irori, and Fabor of Torag.