[Autumn]

?

"If Void Assassin is not your main class, no damage reduction is applied"

With no damage reduction, you can't turn the reduction into void energy.

Now, I think it would be nice if you still generated void energy on being hit and just didn't get a reduction, but this is working as intended as far as I can tell.

If I remember correctly, you would still obtain 15% of the magic damage taken as void energy stored but you do not gain the DR.