Kaz maintains that it's fine (I guess it makes you Prisoner bait, too, not that those Harpies needed more reason to be shut down by him and an upcoming character), but we'll see. The Harpy only really hits that hard against other high-health Sentinels for the most part, and you can't impact the damage of it like you can an Assassin Golden Sun. Still an amazing character, I'll grant you that.
We're actually looking at the potential time for the next major update and considering posting some preliminary tuning notes ahead of that, but there's no planned changes for the Sentinel Harpy.
We are investigating. Thanks for checking with me.