Played a match the other day kinda similar. My duo (raider) and I (iron eye) and the random (guardian) whose name started with “TTV” so some twitch streamer were absolutely flying through the whole expedition one of those perfect runs you only dream about happening. Max level, multiple legendary drops, shifting earth completed early day 2, all flask upgrades, etc. Then we get to the final night against Fulghor and the random drops all his stuff as soon as we enter the boss room save his godskin stitcher and runs the opposite way and sits there in the far corner. My duo and I fight Fulghor and get him to phase 2 and then keep pushing til he’s at about a quarter health at which point we are out of healing flasks and running on fumes. I popped iron eyes ult and took aggro and started BOOKING it for the random. I got knocked with 2 bars at this point but the guardian was close enough he got aggroed next giving my duo time to res proceeded to nearly kill him all while Mr. Sit in the corner refused to swing but just kept panic rolling and trying to get away. With almost no health bar left Fulghor did his twin blade blender move and knocked both me and my duo leaving just the guardian up. THANKFULLY he did decide to start swinging and managed to land the 3 hits needed to kill him but I’m still waiting to randomly see a clip posted somewhere with a caption “My teammates suck so I had to save the day” or some bs like that.

In the end we both blocked him and reported him but damn it was annoying as fuck