This item has been identified as an outstanding known issue. A workaround is provided until the issue is officially fixed.
When module has nested Rows dimension and both empty and non-empty cells in one row,export to PDF with option "Omit Empty Rows" will combine the row to one above.
This issue can be worked around by either below methods:
Use export other than PDF
To not use "Omit Empty Rows" when exporting to PDF
If this workaround is not suitable in your use case, please contact Support at firstname.lastname@example.org.
Internal Reference: CORESRV-3880