Hello -
Are you using Tutu Tweaks? I'm about 99% sure it is one of their components that is breaking wild mages in this way.
Yes I am, but which component is responsible for this new alteration? I downloaded all of the TutuTweak's components except for "Rebalanced Weapon Proficiencies", "No Traps or Locks", "Wear Magical Armor and Rings", "Two-Handed Bastard Swords", "Two-Handed Katanas", "Remove Experience Caps", "Reputation Resets", "Gems and Potions require Identification", "Change Avatar", "Disable Portrait Icons", "Avatar Morphing Scripty", "Multiplayer Kickout Patch","Adjust Evil Joinable NPC Reactions" and "International Weapon Description Fix".
OH, just thought I'd mention that I've, rather unsatisfactorily, solved my problem by using a fighter/wild-mage/thief, and changing it via Shadowkeeper to fighter/wild-mage/thief without being prevented from buying weapons not allowed for single-class mages. It'll mean taking much longer to reach higher levels but it can't be helped.