Chance to poison on hit from gear and tree doesn't apply to spells properly

Chance to poison on hit applies to spells only with envenom support, but I think it should apply all the time.

For example, if I have 40% chance to hit from the tree

Detonate dead has 0% chance to poison
If I support it with envenom, it has 100% (60% from envenom and 40% from tree)
This interaction seems a bit broken to me

I'm observing this too.

Oh lovely, several months old bug.