Wyvern's Flame Breath and Self Ignite, is this intentional or bug?

Ok I'm trying a build that I made following voices from my head, it's basically a smith of kitava using Wyvern's Flame Breath and self ignite.
For the self ignite I'm using "One with Flame", "Self Immolation", and two "Ignite magnitude on you" for a total of 120% reduced magnitude on my self, however I still take damage when self igniting my self, I die in a flash due to ignites from Flame Breath and even testing with spells the reflected ignite deals a lot of damage, I played a similar meele build last league using smith of kitava and some slams attacks and was completely fine the ignite deals 0 damage.

So any one knows if it's impossible to reach 100% reduced ignite on my self or is this a bug?

Just to clarify I use two weapons set and the reduced ignite is on set 1 ( the one I use with the flame breath) and I don't change it mid boss fight so it's only drake form in boss fights.

I know that Flame Breath stacks ignite but 100% reduced magnitude should't deal any damage...

Should I report this as a bug? Or I made something wrong?