Normal Axial CT Chest at Carina — Bronchial Anatomy

A 45-year-old male smoker presents to the emergency department with acute onset dyspnea and absent breath sounds over the left hemithorax. A portable chest X-ray shows left lung collapse. An endotracheal tube (ETT) was inserted 2 hours ago for respiratory support. On review of the chest imaging, the structure marked **A** in the axial CT at the level of the carina is noted to be abnormally positioned relative to the tube tip. Which of the following best explains the clinical presentation and radiological finding?