Soulcleave's summit was nerfed from 750 damage down to around 400 (365 with no power in pvp, 413 with berserker).
Funnily enough it was left out of the recent patch notes. Another 50% nerf to a rev skill. Shouldn't be surprised by now.
EDIT: Will add screenshots . You have to upload them to an external site now instead of directly pasting them like the old forums. Will take a minute.
I'm dumb and forget the elite causes an unlisted fire field, which is where the burning is coming from. However, Soulcleave doesn't seem to work with hammer autos at all. It works fine with sword, staff, and shortbow auto though.
Tooltip of the elite. 365 damage with no power.
413 damage with zerker amulet.
Soulcleave doesn't apply to:
hammer auto attacks
It also no longer works with Icerazor, although it still works with Darkrazor.
It hits twice for one cast of scorchrazor.