Into The Breach Supports?

Into The Breach shows up with 2 empty support slots in the Skill window, but all the supports I've tried to put in it it says "Can't support this skill" and it doesn't show up in the left menu when using an Uncut Support Gem of any level so how do we find out what supports will work with it?

It does work with Vitality and Clarity at least, with no Spirit alllocation - is it intended to buff Darkness and allow Acolyte to have some auras, or a bug?

From my experimentation, the display is bugged - supports you add to Into the Breach do consume spirit but don't lower the visual display.

I'm not sure how this interacts with darkness as I went breach. It's also unclear what the intent is:
- Is it a display bug and it's supposed to consume spirit?
- Is it intended not to consume to work with darkness?