I’ve asked around and I’m apparently not the only one having this problem. Simin seems to be coming out of stealth whenever she wants now. I had a party of 4 dungeon masters (all guildies who have consistently downed her before usually in 10-15 minutes), and she just kept going back into stealth at 25% regardless of how fast we ran the orbs. We’d run them in before she regened up to 40%, and she’d just pop out… we’d hit her for 5-10 seconds, then go right back into stealth at 25%. It’s only been like this since the last patch.
Furthermore, the sparks are still agroing onto summoned creatures, and onto Greyston, the NPC that tags along. Usually not a problem, but we were told that had been fixed.