When you have an assembly with some hidden components, the Creo View model that is creaetd preserves the visibility so all the components would be published but those that were hidden would be off by default when the model is opened in Creo View. However, the thumbnail that is created does not preserve the visibility of the components and all the components are shown in the thumbnail. That means the thumbnail could potentially look completely different than the original cad assembly and Creo View assembly which doesn't make sense.
Suggest to only have the visible components added when creating the thumbnail.
