The problem was that `threading::parallel_for` will return a range containing multiple elements even though the grain size is `1`. Pull Request: https://projects.blender.org/blender/blender/pulls/144826
The problem was that `threading::parallel_for` will return a range containing multiple elements even though the grain size is `1`. Pull Request: https://projects.blender.org/blender/blender/pulls/144826