Cannot use poison arrow skills after refunding Event Horizon

I realise that having both Chaos Inoculation and Event Horizon makes you unable to use poison arrow skills. This is because a life cost is added to them and you only have 1 life.

The bug is that even after refunding Event Horizon, you still can't use poison arrow skills. The cost doesn't correct for the removal of Event Horizon.

I've tried:
- Also refunding Chaos Inoculation and re-adding it.
- Removing gems from a the relevant skills and re-adding them.
- Logging out and logging back in.

Cheers

Never mind. It was a ruby that was causing the problem.