adding this a possible issue since I could not find any other ticket for it.
MC: 1.20.1
Fabric: 0.15.11
Spell Engine: v0.15.8+1.20.1
Wizards (RPG Series): v1.3.0+1.20.1

While wielding a weapon in the off had that has spell casting ability and the user has a spell book equipped.
Right clicking with tool an (pickaxe for example) will cause the user to swap to offhand weapon.

unequipping the spell book or disabling the Auto swap Spear & Bow feature gets around this issue.

Issue I would assume should be able to recreated with any of the RPG Series since they all use a spell book of some type.
Able to recreate with limited mod list above + dependents