When I use Merge Cells in libreoffice calc. It is not getting saved. After reopening the file,changes are lost. Is there a way to counter that?

When I use Merge Cells in libreoffice calc. It is not getting saved.

saved to what?

In what format are you saving your document?

in xlsx format, i am trying to save

by merge cells not getting saved, i mean that when i save the file with megre cells applied to some rows .on reopening the file ,text still appears with division of cells which was earlier removed.

Works here with LO 6.2.4.2 (x64)