I think its safest to assume time travel.

Super weird, yeah. Both the upper and lower ends have some slope, so it’s not just “ghost points”. Thr points are connected in a contour, so the data really is going back in time, then reaching new values.

It gets weirder the more I try to solve it.

Its not a bug its a penguin. Seriously though someone probably mixed up x and y axis in some variable calculation when draeing to the screen.