Regulations Governing Immigration Inspection and Data Collection and Utilization Article 13

For travelers who enter or exit the State through e-gate or those promulgated by the NIA, the exit stamp may be omitted.
中文原文 入出國查驗及資料蒐集利用辦法第13條
經自動查驗通關系統入出國或其他經移民署認定公告者,得免於其護照、旅行證件或入出境許可證件內加蓋入出國查驗章戳。

English translation for reference only; the Chinese text prevails. Not legal advice.