TrinityCore rev. cac4f95 2015-06-06 16:08:25 +0200 (3.3.5 branch) (Win64, Release)
TDB 335.58 + updates up to and including 2015_06_08_00_world.sql

Megzeg Nukklebust (http://www.wowhead.com/npc=21283/megzeg-nukklebust)

NPC ID: 21283
npcflag = 4099 (this is wrong, the NPC is not a repair NPC, he is only a quest giver with extra gossip)

Solution: remove flag 12 (4096) from the npcflag value and make him a quest giver with gossip:

UPDATE `creature_template` SET `npcflag` = npcflag&~4096 WHERE `entry`= 21283;