What is happening?
Having 30 levels in wizard, Maximize feat, and a Spellbound Wand of fireball is not causing the spell to be casted as if it were Maximized.
What is expected?
The spell to be casted maximized if the following conditions are met:
Wizards and Sorcerers automatically Maximize or Empower their Spellbound Wand bound spells if their caster level is >= 50% of their character level and they have the relevant feat. If they have both feats, Maximize is always used.