These two skills have some similar looking nodes on their trees that convert ignite on hit to ignite per second while also giving the option to convert to physical.
But they they actually work very differently. If you take the Ghostflame Arteries of Malice to convert to physical, your resulting bleed chance per second will be based on your ignite on hit chance(which is converted to bleed per second) + your ignite chance per second from “Dread Furnace”. The surprising part is that the bonus ignite per second chance from “Flames of Misery” has NO effect.
By contrast, Cthonic fissure, when converted, still benefits from every point put into Mantle of Flames. Basically, Cthonic Fissure benefits from the ignite on hit to ignite per second conversion while Ghostflame does not. It simply grabs the ignite on hit chance.
I don’t know what the reason for this is and it is very possible that I am missing something and that it is working as intended. But it is also possible that one of these is broken. Actually, yesterday, they fixed the bleed duration on Ghostflame so maybe this is just another issue. Anyone know?