I would never have dreamed of forbidding some material that was already gathered, for fear the moody Dwarf would then go insane.
Rule of thumb for me is to forbid a material, unpause the game, wait 3-5 seconds, pause and see if the mooder stays in the shop screaming for materials or just goes about collecting the rest of unforbidden materials.
I always use the Stone screen to keep shops from using special stone for tables, etc. I don't control manufacturing by forbidding stones en masse from the Stock screens because then they won't get dumped, and anything made of that stone becomes forbidden.
Since I stop every industry when a mood is happening and then inmediately unforbid everything afterwards I usually dont run into this problem, but the stocks screen or a simple [k] inspection makes it simple to track down a problem with a workshop. Granted I dont use the manager much other than to set workshop profiles so when I get a message of "Urish Mc Leatherworker cancels Make Tiger Shark Loincloth: Workplace innacessible" I usually know where to look.
I expected that to work for artifacts and when it did not, I gave up trying to control moody Dwarves. Good work on your part to have learned so much about that aspect.
Nah, Im just autistic when it comes to artifacts because Im always imagining something cool and want to make sure it looks like I want it to. Like instead of using boring llama bone, I want my legendary steel axe to be encrusted with forgotten beast bones that the owner slayed. But thanks for the praise.