Softball rules question: foul tip called late after batter headed to dugout

A 9U tournament at-bat got contentious after a batter with two strikes swung, appeared to foul-tip, and started toward the dugout before the umpire clarified the call and brought her back to finish the plate appearance. The opposing coach protested between innings, raising questions about foul-tip mechanics, when a batter is considered out/abandoned, and how umpires should communicate the call.