View the original community article here
Last tested: Oct 29, 2019
One cause is including a model file in a view file. This is sometimes done in an NDT view file. Then when another model is added which includes this NDT view file, all of the explores from the original model file will show up in both models!
One way around this is to use a separate explore file, and another is to not include the NDT view file in the new model file.