I try to purchase a game from someone's shop in exchange for a Dota 2 Treasure Key.
I have selected the game from his shop and selected the Dota 2 Treasure Key wishlist in his shop, then clicked on Purchase.
After it tries to validate I get this message "Items in your backpack cannot satisfy the wish list specified.".
Why am I getting this message? I have more than enough Dota 2 Treasure Keys in my inventory and it is on public, so those are not the problems.

The any treasure key matcher is broken because the schema is outdated (the automatic update process is not working for some reason, maybe Valve changed something). We will update you if we manage to fix that.

Only the treasure key matcher (not treasure key, but the matcher that matches all treasure key).

I have just tried that the standard treasure key works on purchase (the normal one that is going to expire, not sure about the one that has 'mythical' quality).