'Import a XAR in a wiki' REST API is not working as expected

XWiki version : 14.4.7

To reproduce :

• Create a test wiki page and export it as a XAR
• Edit the page and modify its content
• Re-import the exported XAR in the wiki using the "Import a XAR in a wiki", see documentation, use this curl command to import the XAR :

curl -u "username:password" -X POST "http://localhost:8080/xwiki/rest/wikis/xwiki?backup=false&history=ADD" --data-binary "@/Path/to/the/xar/file" -H "Content-type:application/octet-stream" 

Expected results : The XAR file was successfully imported and a new version was added to the test page.

Current results: The REST service is executed but the import failed, what happen is that the Test page is deleted instead of being updated by the import, see screenshot :

This error is found in the tomcat logs : error.txt.

Note that :

• The issue only happen if the imported page already exists in the wiki, so, if you use the REST API to import a new page the import is executed correctly
• The import is correctly working if it is done manually via the wiki administration
• It seems that the issue is a regression because I don't reproduce it on a 10.11.8 instance