When using first charged attack on Dagger or Fire Sword, no matter how many targets you hit, this talent is not activated. On other weapons it work exactly as I would expect by description, so this has to be bug.
Hit 4 or more targets with charged attack on dagger or on fire sword.
In keep on moded server and in game with dagger (didn’t tested ingame fire sword)
Immersive immolation
Hitting 4 or more enemies with one attack grant 15% incrased attack speed for 5 seconds.
“One attack”
-> Fireball charged triggers it? Check
-> Ultimate triggers it? Check
-> everything else I tested so far triggered it when this condition was met? Check
EDIT: This talent is supposed to bost not only melee attacks but also staff attacks, thats why there is global condition of one attack and 4 or more targets. So it might be better than the rest of the talents on that row, when it is fixed to work with all weapons properly (especially those which benefit from it most)