I ran into the same issue and stumbled about the notebook from @chizkidd (see his comment below). I tested his notebook and it worked. Despite his code changes the only difference was that the environment preferences were set to “Pin to original environment”. I checked my copy of this notebook and it was set to “Always use latest environment”.
After switching back to “Pint to original environment” the error was gone and I was able to run the whole notebook 
Hope this works for you, too.