How can I fix "duplicated text" while sorting in Writer?

When I sort text in Writer, it displays duplicate sorted text on screen - which disappears if I delete just one characters in the sorted text. The text being sorted is in a “section” of text. Is this a setting problem with how text is handled on my computer or a version bug? Do I need to do something about the video drivers on my PC (I’m using an AMD Radeon HD 7700 series video card)? I’m using version (x64) on a Windows 10 Home PC.