> Sorry, this is still not detailed enough: how did those "new parts"
> appear, and in which buffer?  IOW, what did you do to make these new
> parts appear wherever they appeared?


> I'm asking for more details about the "was written" part.

It happened again. In a latex file I currently edited, parts of edits
disappeared. Fortunately I had backup-each-save activated, which makes a
backup copy (in a separate directory) of the whole file each time the
file is saved.

It looks like 
36K ene 11 18:23 new-report-vs2.tex-2024_01_11_18_23_52 edits lost
36K ene 11 18:23 new-report-vs2.tex-2024_01_11_18_23_43 edits lost
36K ene 11 18:23 new-report-vs2.tex-2024_01_11_18_23_41 edits lost
36K ene 11 18:22 new-report-vs2.tex-2024_01_11_18_22_37 edits lost
36K ene 11 18:21 new-report-vs2.tex-2024_01_11_18_21_27 Good file

I have to finish this report and then I try to come up with a MWE.


-- 
I strongly condemn Hamas heinous despicable pogroms/atrocities on Israel
I strongly condemn Putin's war of aggression against Ukraine.
I support to deliver weapons to Ukraine's military. 
I support the EU and NATO membership of Ukraine.