Visual bug in memory plot

When leaving the task manager to run until the memory plot fills up all the way (~15 min), I always notice this weird diagonal line in the memory plot. It goes from the top left to the bottom right:

The whole area under the line should of coarse be colored pink like it is before the plot fills all the way:

I am using Version 1.5.2

Just noticed the same happens to the CPU plot, but it isn't as noticeable because it's usually very low.

I think it should be an easy fix, maybe I will look into the code myself when I have the time.

Good luck and thanks for the awesome free software you people develop!

  Operating System: Linux Mint 20.3

  Kernel: Linux 5.4.0-126-generic

  Architecture: x86-64