The automatic realtime save is not performed all times with the last user that made a modification

Steps to reproduce

Initially this issue was reproduced while testing in real time with Gabi, but I also managed to reproduce it locally with 2 users in different tabs (one using Incognito mode), though, not that easy.

1. Enable Realtime WYSIWYG from Administration
2. Login with an user (e.g. U1)
3. Edit a page (I reproduced by editing in-place, if relevant)
4. Using another (incognito) window/tab, login with another user (e.g. U2)
5. Edit the same page by forcing the lock
6. Create a line of text to be only edited by U1 and one line just for U2
7. With U1, add some text in its line
8. After that, with U2, add some text it its line as well in order to be the last user who makes a modification
9. Wait for the automatic save to occur

Expected results

The automatic save is performed by U2, the last user who made a modification.

Actual results

The automatic save is performed by U1, the user who started editing the page.

The issue is not quite easy to reproduce, as it required a few tries (edits) to be able to reproduce it.

Please see attached the screenshot, including the diff.