Not sure why my CI is failing for a Particular Version?

[giordano]

Yes, having the Manifest.toml checked in doesn’t place nice with running CI with multiple Julia versions, as the Manifest.toml is intrinsically specific to a single Julia version and CI instantiates the Manifest.toml:

Does Manifest.toml belong in the repository?

Yes, I also had a fair share of troubles with CI because of a checked-in Manifest. Note also that if you have a checked-in Manifest and bump the compat bound of a package without updating the Manifest, you still test the old version. Also, the Manifest is specific to a Julia version, which may not play very nicely with running CI across several Julia versions in some cases