Quran.com Feedback Team
Assalamu Alaikum Dear J,
Jazakum Allahu Khairan for your message.
After reviewing the Juz division, Juz 20 ends at Surah Al-Ankabut (29:45) and Juz 21 begins at verse 29:46, which matches the standard Mushaf division and the display on Quran.com.
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Quran.com Feedback Team