Guild Wars 2

Dying/downing to agony while transformed (tonics, boombox, etc.) results in your character having 0 agony resistance after reviving/rallying.

Subsequent deaths or rallies do not restore agony resistance. Unequipping and equipping the items that give AR does restore AR.

Just a small inconvenience when trying to entertain my party members with a boombox before Molten Boss. Needless to say, I wasn’t too helpful in the fight.

Thanks for the report. You apparently aren’t alone in entertaining party members:
https://forum-en.gw2archive.eu/forum/support/bugs/Missing-agony-resistance-fractal-40/6084123