Strange bug when adding ties in this score

Suddenly this bug appeared when in the middle of writing a score. See pictures for best explanation.
It appeared when adding a tie between two guitar chords, and it looks like somehow the middle tie of three is going bananas, covering the score in black. When pressing the tie key again, the blackness disappeared, but the pair of eigth-notes were stretched out to the far right in the score. You can see how far in the inspector. It is only present in continuous view, but still annoying nonetheless.

Not something I can't work around, but It would be fun so see if you guys know the reason. I'm also interested to see if you can reproduce it at all.