The black line is the main keyword. I think that it jumped up because of a refresh and then went back down because the page has too many backlinks with that anchor pointing to it (anchor distribution problem). In the second image you can see the same keyword in red for a longer period of time. You can see that it tries to go up but something is blocking it every single time. What could cause this? is it an anchor distribution problem, on page keyword density or something else? Did anyone experienced such a pattern?