I checked with the Atlassian community if they too have found the quality of the EXPORT with comments to be problematic...but didnt find anything.
What I mean is:
I tried using this feature (Export RSS with comments) but ran into qualitative issues.
1.
When I export the records using the option (Export RSS with comments), the number of tickets exported by JIRA XML export is fewer than the actual #of tickets. The other option of exporting to XLS works fine and retrieves all the tickets.
2.
Secondly, when exporting using the RSS with comments, I also noticed that not all the comments are exported out. Many of them are, but some are not. This is as of Oct 28, 2022.
3. Opening the XML in Excel throws some errors which needs to be manually fixed. This is a minor issue. But 1 and 2 are more important for me to address.
Feel free to comment on the quality aspect if your experience has been similar.
I can provide the proof to Atlassian by opening a support ticket/request to further investigate this.