Running the Harpies, the Harpy Queen spammed Scintillating Sphere five times, -subduing- the party. Then the other harpies killed them. I ran around in circles using all my healing and clarities while she cast lesser dispel on me repeatedly (about five to 7 times as well) resulting in a FPW.
The Harpy Queen is likely a fairly high level sorceror class (accounting for the spamming) or the Scintillating Spheres are part of its special abilities. Either way the fact that it subdued your party means a DM was likely present, and this was spice and not a bug.
The Harpy Queen can cast this spell regardless.
We did the Harpy Quest with a party of three, and overall, the spawns weren't entirely difficult. They felt balanced, as they generally do. At the final room, fighting the queen, she cast scintillating sphere multiple times, subduing my character before chasing after Wafflecone's.
Upon being subdued, the other harpy targeted me, putting me at negative HP, in which I bled out.
I fear not only is it a bug that the queen cast SS so many times, that she was on subdue also, which eventually led our team to a full party wipe.
This was not a spice, and it's common knowledge that she can cast the spell, but it's rare that anyone sees it cast above 3.