When you place the cursor in the last cell of the table and add a new row using the Tab key or the add new row button, the formatting of the entire table is cleared.
I can not confirm that. Version: 25.2.0.1 (X86_64) / LibreOffice Community Build ID: ddb2a7ea3a8857aae619555f1a8743e430e146c9 CPU threads: 16; OS: Linux 6.8; UI render: default; VCL: gtk3 Locale: ro-RO (ro_RO.UTF-8); UI: en-US Calc: threaded Red text on the last row, tab from the last cell, the new row have red text.
*** This bug has been marked as a duplicate of bug 126008 ***