There were already complaints about AI targeting lowest AC. It's not entirely stupid move. I have myself often targeting enemy mages in games because they can cause alot bad blood during fights. Wizardo are mostly squishy unless guarded by some powerful spell. However AI should adjust their tactic when there is some bottleneck like doors. It would be cool to have AI not jumping into fight like headless chicken but going sides and trying to clear the pathway 1st.
Agreed, I have done this also, unless there is a more immediate threat right in front of me (the fighter and cleric in this case). I can't foresee an archer charging to their doom (especially selfish bandits) just to take out the wizard for their compatriots. This is where the tactical maneuvers of setting up the tank and other threats in front of the wizard. If the AI is going to target them regardless, it kinda removes the concept of battle tactics.