I couldn't find a bug report link on LibreOffice.org so I'm sending it here.
Steps to reproduce:
Navigate to a folder in the Finder that has more than 1 .odt file.
Select two .odt files.
Open them (Command + O).
Expected outcome:
LibreOffice should open both documents.
Actual outcome:
LibreOffice puts up an error dialog with the following message:
/path/to/document1.odt /path/to/document2.odt does not exist.
It seems LibreOffice does not correctly handle opening multiple documents at once, treating both filenames as one filename (to a file that does not exist).
It does not matter if LibreOffice is running or not. Opening one document at a time works as expected, it's only multiple documents that fails. I'm not sure if this affects older versions. I may not have attempted to open multiple documents until today.