>7. This incident has reminded that many people mistakenly assume that git tags are immutable, especially if they are in semver format. Although it's rare for such tags to be changed, they are not immutable by design

IME, this will be more "learned" than "reminded". Many many people set up pipelines to build artefacts based on tags (e.g. a common practise being "on tag with some pattern, then build artefact:$tag") and are just surprised if you call out the flaws.

It's one of many practises adopted because everyone does it but without basic awareness of the tradeoffs. Semver is another similar case of inherited practise, where surprisingly many people seem to believe that labelling software with a particular string magically translates into hard guarantees about its behaviour.