Infernalist Demon form - Support gems don't work at all

When using support gems to support Demon Form (Vitality, Mysticism, Clarity etc) their effects don't apply at all, and they are seemingly disabled entirely.
They also do not make the clink sound effect when socketing/unsocketing that every other support gem makes.

I noticed it after unsocketing Mysticism didn't change the tooltip damage of any of my skills, even though Demon Form was active and I was at maximum energy shield. Then I tried the same with Vitality and Clarity and the Life regen and Mana regen stats on my character sheet also did not change.

Also the support gems say that they add a spirit reservation cost, right now the supports I have in it should cost a total of 50 spirit, but when entering Demon form my spirit just stays at maximum and does not get reserved at all, which implies they are straight up not working.

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With Mysticism socketed, Arc DPS is 1355:



With Mysticism unsocketed, Arc DPS is still 1355: