Hi @jvachez, that check only tells you the folder exists, not that the venv inside it still works. If the cache was restored from a fallback key, or the Python version in the image changed, you can end up with a venv that has a broken interpreter link or is missing packages, so pip install gets skipped and the import fails.
I’d tie the cache key to both the requirements file and the Python version, and always run pip install (it’s quick when everything is already installed):