What is the correct scholarly response to the readings la-tarkabunna / la-tarkabanna?

Supplementary Practice 29 — Comparative Rhetoric of Sūrat al-Infiṭār and Sūrat al-Inshiqāq

• One of the readings does not exist
• Both remove emphasis
• The readings may alter the interpretation of the addressee
• The word ṭabaq loses all shared senses