In a cell I used the button with the percent icon "%" (located in the cell formatting tab under number format) to make numbers as percentages, instead of manullaly multiplying by 100. This however was not correctly recognized with libreoffice calc. Reproducible: Always Note that files edited with libreoffice calc are backwards compatible with calligra, but not the opposite.
Created attachment 85025 [details] The original file created by calligra sheets
Created attachment 85026 [details] Same file edited with libreoffice
Works in current version of Calligra, so closing.