What is the name of inattention/autopilot phenomenon that results in 'swapping out' errors
The Stroop Effect is more for rapid-fire tasks and task switching.

Unconscious Thought Theory may be related.

Absent-mindedness can lead to automatic behaviors or automatisms.

Highway hypnosis is similar, where you don't remember the task you've done even though it's correct.

Otherwise, making a mistake due to habit/habituation?