Arcanist Brand with CWDT?

Hello fellow exiles,

I was recently trying to create a build with a spellcast loop, consisting of 2 ngamahus signs, eye of innocence and CWDT.
Now when I link all together, the CWDT triggers my spell, fireball in this case, instead of arcanist brand.

Is this intended as I read that you can trigger other brand skills with COC or CWDT, and the arcanist brand does not state that it would handle this different?