Client Crash Bug at Underground Facility Fractal boss?

The other day I was doing the T1 daily Underground Facility, and I had a disconnect at the final boss (we had the ice elemental). Upon reconnect, and staying dead waiting for the boss to die or the party to wipe, within 5 minutes I got an error message stating "Assertion: Tried to remove a buff that isn't (or wasn't) applied". This happened like four times as I was lying there dead. On a second boss attempt, it was another party member who got disconnected and on relog he came upon the same crash while waiting dead.

So, my question is... has this happened to other people? Is it reproducible? Since I game from Linux, my client isn't supported, and as such any crashes here will be ignored, but if it happens to Windows users as well, then it's a legit bug that needs fixing. Also, it doesn't happen if you die during the encounter, only if you join the instance and appear dead during that fight :P