I have implemented the Hertel-Mehlhorn algorithm to optimize my navigation mesh. As you can see in the image there are many cells that are long and thin. This happens when I have large open spaces.
Is that a known behavior of H-M algorithm or do I do something wrong? Is it possible to somehow define a maximum width of a cell? Or are there other ways to deal with this?

(Please ignore that the diagonal obstacles produce a pixel-like effect, that's a topic for another post).

Thank you!
Cheers,
Martin