I customized my LibreOffice Calc default template as described here so that all new spreadsheets created in the application have this formatting. However, I noticed that CSV files opened in LibreOffice Calc from shell using
xdg-open did not use my default template.
This turns out to be an old bug in LibreOffice Calc known for many years. There does not seem to be any estimate of when this bug will be fixed.
Tried with: LibreOffice 126.96.36.199 and Ubuntu 18.04