Yea we are aware of this bug, unfortunately our custom quest writers aren't sure exactly what causes it... you can fix it for yourself though by placing the facade block down, re-logging and then breaking it again, and then when you pick it back up it should submit fine.
Hmmn, I had someone just the other day with the same problem and they followed that advice and it worked fine for them.. don't worry about it, I'm logging in now, so I can forcibly complete it for you. Edit: Done.
An unpainted conduit can't be placed in the world and for the quest, it needs to be a diamond block painted conduit. Chaosblad3's suggestion didn't work for me but it did lead me to try the following (which did work): - Preload a crafting table with the blank conduit materials - Preload the painter with the diamond block - Log out and log back in - Immediately craft the blank conduit, paint it, and submit it Good luck!