Thariel, the Umbral Wraith Telegraphing...

Just did a Riverhold map where "Thariel, the Umbral Wraith" was the boss. Did I miss something or is this boss not in the campaign?

Anyways, the telegraphing of attacks is non existent, which causes me to die almost instantly because I got no clue what is going on.

Did this escape 0.4 internal testing?

It's not just you. This boss is complete bullshit for some builds. My mercenary archer has no problem. On my monk, I just don't ever do riverhold, now that bosses are mandatory.