In a calc document, type "This is a test" in a cell. Then highlight just the word "test", and select Format -> Character -> Position -> Superscript. Now, save the document in the .XLSX format. Reopen the document, and the superscript will be applied to the entire cell, not just "test". Saving the document as a native Libreoffice format doesn't exhibit this bug.
Hello, should be resolved in version 5.1 *** This bug has been marked as a duplicate of bug 93115 ***
Thanks!