I am trying to simplify a layer made of polygons. I have used different methods but the new simplified layer has a polygon which intersect with itself, thus creating a "new" polygon. Please see screenshot below for an example. The darker line is the new layer and instead of following the original line (you can see all its vertices as red crosses) it cut across to reach the top left vertex. Is there any method/settings that I can use to force the simplification to follow more strictly the original layer boundary?
I have tried douglas_reduction with a Maximal Tolerance Value of 0.000001 and Percentage of point of 99 and it worked if applied to ONLY one polygon. If applied to the whole layer I still have the result shown in the screenshot.