Militant Faith not reducing ignite duration

Hi, I think this is a bug, I bought a firesong thinking I could stack 50% elemental ailment reduction with my militant faith and then have the firesong double that for all the other ailments, with the exception of ignite itself, so I get full ailment immunity (minus the ignite) on just 2 jewels.

Which should work as you see on the first picture ignite is counted as an elemental ailment if I press alt while hovering my mouse over the militant faith, but on my character sheet there's no ignite duration reduction, only the other ailments appears.

But when I put in the firesong the ignite duration reduction then appears, even though it shouldn't make a difference because in the first picture it showed no ignite duration reduction and the firesong should only increase the reduction for the other ailments and not give me ignite duration reduction, but I get the same duration reduction for other ailments that I already had without the firesong.

So to me it seems a bug, or maybe I'm misunderstanding the interaction, any help would be appreciated, thanks.

Images for reference



https://freeimage.host/i/Hxr4DPa
https://freeimage.host/i/HxStEPe