Vaal gems/CWDT

Is there any reason that Vaal gems cannot be triggered by the Cast When Damage Taken fires?

I have put Vaal Haste in the setup with CWDT and two things happen.

1) When it should trigger, it does not (and, yes, the necessary 'souls' are there)

2) It can be manually cast, unlike other curses or spells linked to CWDT that cannot be manually cast.

Thanks in advance for your assistance.

Right, it's intentional.

"

1.2.1 Vaal skills can now trigger other skills. Like before, they can not be triggered themselves.

Thanks. Not where sure where u found that, but I appreciate the reply.