Describe the bug

A recipe with the following preprocessor

  preprocessor_1:
    extract_levels:
      levels: bcc-csm1-1
      scheme: linear

fails when the reference dataset (here bcc-csm1-1) needs to be downloaded (with offline=False) since the loading of this dataset already happens in _recipe.py prior to downloading:

Please attach
recipe_test_reference_levels.yml.txt
main_log_debug.txt