I find my explosive arrow build always having problem of incapable to ignite the boss, even with above 100% chance to ignite.
https://www.youtube.com/watch?v=mImj6DDJhLQ&feature=share (self attack: 101%, Totem: 98%)
And here is a video of me fighting Baran, there are no map mods so there should not be mod like "monsters have chance to avoid elemental ailments". As you can see only the forth explosion caused ignite in the video, and the other three explosion only deal explosion damage but without igniting the boss.
Tooltips that showing my character has 101% chance to ignite:
My character:
Edit: Some people suggested that Ballista Totem is the cause of not igniting, that's actually seem true, I am most likely incapable to ignite the boss when I pull down the ballista totem and attack the boss with my totem. I am still doing some experiment to test out is this actually the cause, but I think Ballista Totem is mostly likely the reason.
Video of fighting Drox without Ballista Totem (Ignite at first explosion)
https://www.youtube.com/watch?v=avXRhWJ3FY8&feature=share
Edit2: Someone pointed out that chance of ignite of ballista totem is the cause, I reviewed my build, I was using a 20lv 20Q Explosive Arrow Gem on the totem setup leading the ignite chance of the ballista totem is 98%. I fixed it with a 20lv 23Q Explosive Arrow Gem which now make my totem have 101% chance to ignite, and retry it on the Hunter fight, but getting the same result with the Baran fight which I only had 98% chance to ignite on Ballista Totem. In the Hunter fight, the first two explosion still doesn't cause ignite damage, but after my totem died, the third one immediately melt the Hunter.
https://www.youtube.com/watch?v=6sPXk1EpTwE&feature=share (self attack: 101%, Totem: 101%)
Edit3: One guy in the comment section find out that sticking too many arrows on one target would resulting in no ignite damage. I also tested it myself and I believe that this is the true answer. GGG pls help.
Edit4: Turns out that too high DPS is the real issue, stacking too many arrows is just a factor that lead to too high damage, I tried to fight bosses fight with 3 link and 4 link setups, stacking as much as arrow I can, explosion applied ignite on first explosion.
4 link: https://www.youtube.com/watch?v=lm9PYQBBeSo&feature=share
3 link: https://www.youtube.com/watch?v=utvd090ftMg&feature=share