How to avoid merge cell in excel

The reason for that is the cell that is wrapping is increasing its height to fit the text, while the other cells in the same row are not doing the same thing. You should try setting the Stretch Type to Relative to Tallest Object and see if that helps.

Credit to https://stackoverflow.com/questions/9511353/jasperreports-merge-cells-exporting-to-xlsx?rq=1