Duplicate Vaal aura skills with Clayshaper

My Vaal Discipline and Vaal Purity of Ice are generating 3 skills per gem, 2x normal + 1x Vaal. I have both of these socketed in a Clayshaper. If I swap Discipline with Vaal Purity of Lightning (in an unset ring), the problem switches to PoL. If I swap instead with (non-Vaal) Skitterbots, the problem does not manifest. So the issue appears to be Vaal gems in Clayshaper. I haven't tested other weapons that grant skills.

Only one of the duplicate auras can be enabled at once. I can enable the other copy but then the first disables. If I reverse the process, the 2nd one stays enabled, which is odd.