Pass null as forEachFeatureAtPixel layer arg for unmanaged layers #4391
Features on the removed
See #4143 (comment).
@bartvde I meant you should look at my branch to see if it makes your life easier, so you don't need a code snippet like the one you posted in your application.
Your issue is unlikely to be fixed with this branch, but it might. Because now forEachFeatureAtPixel is only called once for features that are on multiple unmanaged layers.