Learning Elixir Skills is Weird

To train either elixir skill, the other must be set to untrain. That's fine and makes sense, but if you have only unlocked one of these skills, you cannot set it to train, because the other isn't set to untrain. In other to use either, you must buy both, which doesn't make much sense. If you've only unlocked one, you should be able to train it, as there is no benefit being gained from the other.

Also, elixir receptive is a t2 skill that costs 1000g to unlock, and elixir extension is a t4 skill that costs 100g to unlock.


edit: To be more specific, yesterday I unlocked the Elixir Receptive skill. It was intitually set to untrain in the skills UI, and clicking the arrows to set to train did nothing. After buying the Elixir Receptive skill, I could then set the Elexir Receptive arrow to train.

 

The 2nd other "In other to use..." --> order

It works for me. I have only learned "Elixir Extension" from the Tactics school and left "Elixir Receptive" in the Focus school as not learned.
Elixir Extension is now at 40 so I can train it without having ER.

 

Receptive was the one that I unlocked first, and it was stuck on unlearn until I purchased extension. Maybe they have a default train/untrain setting even when they are still locked, and receptive is set to untrain.