Great question. Could it come down to a difference in reading strategy combined with cognition? If one ponders when we write we kinda' write in the past. The writing follows behind our thinking. That said, even when we edit our own work there may be a three step process occurring.
We are reading while our thinking is still far ahead. Being familiar with the work making a change even follows farther behind those two. Humorously making a change may be kinda' like a nuisance very quickly forgotten since the main idea has been stated or is further ahead. How are we reading at that time? Is that why it is suggested to read aloud?
Contrast an unknown work where our cognition occurs as we read while we infer. If what is inferred does not occur we hesitate. Something does not make sense. Here is where reading strategy may impact with purpose. What reading strategy is implemented?
Reading for main idea and purpose
Reading for information to answer a question(s)
Reading for comprehension seeking facts
Reading for story structure
Reading for pleasure
And, then reading for editing as a purpose
Something simply does not make sense for a reason. Very likely that is the grammar or language. At task is those two must match the flow and the logic. To make sense something must change. While reading cognitively we will hesitate and make the change, even though we do not know what the future holds. We hesitate, slowly read ahead, cognitively decide that point something did not make sense, and then decide if a change is necessary.