You are our letter inscribed in your hearts known and read by all men

One cannot always rely on translators and their decisions of what the text contains. Every time I come to this passage of scripture, I am dismayed at the rendering and decisions of translation committees. It starts with the editors of the Greek text which give the reading an “A” though it can’t be correct.

Most English translations read the verse as: You yourselves are our letter, written on our hearts, known and read by everyone (NET). Some translations will have a note saying that the alternative reading is “your” hearts. Sinaiticus has “your” which is the correct reading while Alexandrinus and Vaticanus read “our.” Most extant manuscripts read “our” but what exemplar was in front of the copyists?

If the correct reading was in an early manuscript that was kept in a desert monastary while the errant text was recopied numerous times since it resided in a large city, which one is valid?