RegexRemovePreprocessor not working with notebook output format

[DrDrij]

It appears the RegexRemovePreprocessor works with default output HTML, however, ignored when using -- to notebook

https://github.com/jupyter/nbconvert/blob/master/nbconvert/preprocessors/regexremove.py

Works correctly:

jupyter nbconvert --RegexRemovePreprocessor.patterns="['pattern']" file.ipynb
[NbConvertApp] Converting notebook file.ipynb to html
[NbConvertApp] Writing 275715 bytes to file.html

Creates duplicate notebook file:

jupyter nbconvert --to notebook --RegexRemovePreprocessor.patterns="['pattern']" file.ipynb
[NbConvertApp] WARNING | Config option `template_path` not recognized by `NotebookExporter`.
[NbConvertApp] Converting notebook file.ipynb to notebook
[NbConvertApp] Writing 20390 bytes to file.nbconvert.ipynb

[BKJackson]

I'm receiving the same warning when I try to clear notebook cell output

$ jupyter nbconvert --ClearOutputPreprocessor.enabled=True --inplace $file
...
[NbConvertApp] WARNING | Config option `template_path` not recognized by `NotebookExporter`.

Does the jupyter_nbconvert_config.json file need to be changed? It shows the following:

{
  "Exporter": {
    "preprocessors": [
      "jupyter_contrib_nbextensions.nbconvert_support.CodeFoldingPreprocessor",
      "jupyter_contrib_nbextensions.nbconvert_support.PyMarkdownPreprocessor"
    ],
    "template_path": [
      ".",
      "~/Applications/miniconda3/envs/py36/lib/python3.6/site-packages/jupyter_contrib_nbextensions/templates",
      "~/Applications/miniconda3/envs/py35cycle/lib/python3.5/site-packages/jupyter_contrib_nbextensions/templates"
    ]
  },
  "version": 1
}

[BKJackson]

Update: Removing the "template_path" section from the jupyter_nbconvert_config.json file made the warning go away.