Personally, I never had any issues in pugs with this boss, even when the dungeon was first launched. Maybe it's a data center thing.
I dunno, but I've had many runs where Giruveganaus was a run-ender, kinda like the first boss of Cutter's Cry, any of the bosses in Copperbell HM (but primarily the first one, more so when the dungeon was newer), the first and last bosses of Pharos (more so when the dungeon was newer)...

Needless to say, it's always just that much more frustrating when the run-ending encounter happens to be the last one in the dungeon.