Created attachment 171340 [details]
screenshot showing the issue with the gtk3 VCL
When using LibreOffice with the gtk3 VCL the right and top page margins are always synced so that they cannot be set independently.
I double checked with the gen and kf5 VCLs and the bug is not there.
Created attachment 171341 [details]
screenshot showing that the issue is not there when using the kf5 VCL
This is a strange bug. I can reproduce it reliably on Debian with the version in Debian backports (1:7.0.4~rc2-1~bpo10+2) but not on Ubuntu (version 1:7.0.5-0ubuntu0.20.10.1).
Maybe it is a Debian packaging bug? I would be glad if someone more familiar with LibreOffice than me would take a closer look at this.
I think this is a duplicate of bug 138471 which was indeed present in 7.0.4 but fixed in 7.0.5
*** This bug has been marked as a duplicate of bug 138471 ***