Yeah, funny 
. But truly, asking for a lecture code (a notebook or else) to be reproducible only exactly with the set of packages with which it was created, ignoring that packages got bug fixes and feature upgrades is not reasonable. This is not what we ask for packages, which have much more flexible compatibility requirements.
What Iām imagining there is that āinstantiatingā a notebook should be similar to installing all packages with appropriate compatibility. Which is what happens when one adds the packages one by one by hand and there are compat entries in the Project.toml. And this is less demanding for the proliferation of package versions installed, and compilation, etc.
As a general rule, only the latest non-breaking versions of each package should be installed, unless in very specific contexts where exact reproducibility is relevant, like when chasing bugs.