I did a lot of testing and figured out what's one culprit: the spline used for the road must start and end outside the polyline of the forest generator, otherwise sometimes it's not detected correctly

I have the same issue with patch 1.2. Some roads are correctly cleared and others don't. All the generators are correctly configured to Avoid all roads and object

I figure out it was related to SoundWorld_Base.et not having the proper .smap file. Once I set it correctly the crashes are gone.

I think I've found the problem: my Default layer was locked and that probably caused the Auto Occluders in the GenericTerrainEntity to not work correctly. Once I unlocked the Default layer the issue is gone.

I have the same problem: on my map I've placed the forests first and then the roads. Sometimes they are correctly detected by the ForestGenerator and sometimes not. The "break prefab" fix mentioned it's not working for me.