While collaborating in a document when conducting action of Text Replace & entering a comment as user 1, the comments/replies entered is not displayed in the Summary Pane of viewer for all users
Please see attached video cast.
Your replication step is not correct.
It does work as you have shown in our integration as well.
But try opening two different instances, simulating an actual real-time collaboration. In our case, I used one IE and the other Chrome with both different users.