This is probably a "working as intended" but I thought I'd mention it. How I noticed it was that my "shoes" for a class disappeared after I collected the reward from a different class guildmaster. (For reference this was the shoes made by carpentry, but had been equipped on all the tradecraft classes)

I then noticed when I went to replicate the problem, that this kept happening. Regardless if it was a NPC item, even if it was crafted by someone else. The Square Maple Shield, and the Leather Choker did the same thing.

It looks like it might not be working as intended if you can just fulfill the quest with NPC purchased items, or items crafted by others. But it's really annoying to have items you reserved for your other classes disappear.

Time: 9/16/2013 1pm, but not relevant
Frequency: Can be reproduced with all tradecraft guildmasters
World name: Excalibur (but likely applies to all)
Character name: n/a
NPC name: Beatin (also tried Geva)
Monster name: n/a
Class/Level: Carpentry lv5, (also tried Leathercraft lv5)
Party or solo: solo
In-game time: not relevant
Area and coordinates: not relevant

Steps
a) equip NPC or crafted item not made by you, purchase or craft the rest for the quest
b) talk to class guildmaster to complete the (level 5) quest. The guildmaster will take all the items, even if they are in the armory chest

Expected behavior is to either:
a) Reject items in the Armory Chest
and possibly
b) Reject NPC/crafted items that aren't signed by you, or have items you didn't craft not be counted by the quest.

This is technically two issues (the items being removed from the armory chest, and the guildmaster taking any items of the requested type regardless of you having crafted it or not) but seems like it's caused by the same bug.