Edit: It is to note that I did upgrade Knit to 1.7.0 at one point before attempting to update the package back to a previous version; not sure if that would be a factor here.
After taking a break I remembered how it goes. For a while I’ve been only using the latest versions.
By default Wally mimics the behaviour of Cargo or npm with a caret ^. Bug fixes and new features are added while backward compatiblity is retained, so minor and patch versions are always up to date, and major is retained (e.g. 3.y.z). An attempt to rollback from a major to major release will work as anticipated.