Is it true that Ibn Mas‘ud recited Surat Ash-Sharh as: "وحللنا عنك وقرك" (and We removed from you your burden), and why is this recitation not written in the Mushaf if it is authentic?

This reading was narrated by Ibn Abi Hatim, Al-Suyuti, and Al-Tabari from Mujahid, from Abdullah ibn Mas'ud, with the wording: "{And We relieved you of your burden}" [وحللنا عنك وقرك]. Ibn Atiyyah also mentioned it. Similarly, Ibn Jinni mentioned the reading of Anas: "{And We removed from you your burden}" [وحططنا عنك وزرك]. These non-mutawatir readings, even if their chain of narration is sound, are considered interpretive or anomalous. They can be used to explain the meaning and derive rulings, but it is not permissible to recite them or write them in the Qur'anic manuscripts due to their lack of the condition of mutawatir transmission.