Same problem reported in bug #231616 (that was for KDE 4), so I just report here the description: "I have dynamic wrap enabled. I've written quite long texts onto the same line and when I slowly, carefully scroll the document, I see it jumping forward from one line to another (as a top line). It makes scrolling very jerky and thus quite difficult to follow in means of document length." Kate version 17.12.03
*** This bug has been marked as a duplicate of bug 256561 ***