Flame Totem proccing on kill effects on character

I have been running a dual flame totem build with a Sire of Shards. I noticed that when using my Daresso's defiance chest that I was obtaining the endurance charge on kill for kills made by my totem. To check I turned off all heralds and my golem, so that there were no outside damage sources. I am using the ancestral bond keystone also so I cannot deal any damage myself.

I have included a screenshot showing that I have received the endurance charges below:



I have read online that perhaps the enemies killed by the burn from my flame totems igniting targets gives me the endurance charges, although I am not sure on this. I did not gain charges for every kill, but such a large majority that I do not believe every single one was killed by an ignite.

I have also tested this with a death's oath chest and I sometimes gain the chaos damage on self on kill debuff also, although because of the chaos damage to enemies this was harder to see if it is bugged, as the chaos damage to enemies may have been killing some.