For the Hammer's Hoard PoI, I combined my two pieces of the LoD plate and traded that to Frodak. I did the first puzzle (the one with the dredge laser guns) to get the purple plate. I've been back to that room and killed the Graveling over half a dozen times and am not getting the next plate.
Any clues on how to continue?
For the immediate moment, that character got the POI by accepting a mesmer teleport into the room (Teleport to Friend isn't enough, because you are booted out of the room.)
If you arrived to this thread midway through, use LFG to find someone porting to the green/treasure room and start at the third step (i.e. take the port, grab the hidden treasure).
It is not worth trying to kill the Graveling and force it to drop its plate; it simply wastes too much time that you don't have.
"Face the facts. Then act on them. It's ...the only doctrine I have to offer you, & it's harder than you'd think, because I swear humans seem hardwired to do anything but. Face the facts. Don't pray, don't wish, ...FACE THE FACTS. THEN act." — Quellcrist Falconer