More section planes active than required

When rendering a Sketchup model with a particular section plane active, AO activates other section planes and only half the model is rendered. The section plane is defined in Scenes and looks fine in the Sektchup window, but selecting render within the AO extension activates other section planes.

I’m using

  • Sketchup Pro 2020 v20.2.171
  • OS 11.1

Any suggestions? (apart from stripping my computer of every file and rebuilding)

regards

Alex Liddell