Comment 2 for bug 1897429

I'm not sure what happened here.. Were you at 6.4.2 on a focal system trying to update your system when you hit this error? 6.4.2 is a few versions old and as you might imagine it's not feasble to test all upgrade paths. Perhaps a reinstall of the package would fix the issue. Could you please try to uninstall libreoffice and reinstall it?

$ sudo apt-get remove --purge libreoffice*
$ sudo apt install libreoffice