This is still an issue in that:
Releases page page is out of date; latest is 2.27.

Tags page shows 2.28.1
Jenkins plugins page shows latest release as 2.28.1
GitHub CHANGELOG.md shows 2.28.1 (July 16 2021)

cc:pjdarton

I'm afraid that I'm not in a position to help with any of that; I'm not familiar with the automation magic that makes that happen and I'm not a maintainer of this plugin (and have little wish to become one - my boss thinks I spend too much time tinkering with Jenkins stuff as it is).
My only involvement with this plugin has been to use it, and thus I ended up reviewing the existing bugs etc reported. I marked JENKINS-61049 complete because I saw that the docs had been moved (and because it's easier to review JIRA issues when their status is up to date. duplicates removed etc).

...but I can say that, on my browser at least, everything seems to be consistently saying 2.28.1 is the latest. Maybe it's a browser/caching issue causing you to see 2.27?

Ah, I think I see what you're seeing, and it's all down to "GitHub Releases" vs "git tags".
GitHub invented this concept of "releases"; this is a GitHub-proprietary thing - it's not supported by git itself and, worse, the GitHub Web UI confuses GitHub Releases with git tags (very long standing bug that renders the functionality nigh-on useless IMO).
AIUI, a Jenkins plugin release (mvn release:prepare release:perform) uploads to the maven repo and puts a (git) tag into the (git) repository and that's "the release" done as far as Jenkins's side of things is concerned.
My guess is that there's commonly been an extra GitHub-specific step to make a GitHub Release from the git tag, but this extra (manual?) step hasn't been done since 2.27
...and IMO shouldn't need to be done - extra/manual tasks aren't a good idea for a release process.
What's odd though is that it looks like it's been the same maintainer doing all these, so I'm not sure how/why the process changed.

TL;DR: I'm seeing the same "latest" GitHub Release as you are ... but the Jenkins release information is correct.

Disclaimer: my plugin release process knowledge is out of date - there may be ways of automating a GitHub Release as well as a normal-for-jenkins release these days - and the fact that this plugin uses a manual changelog file suggests it's doing things "old school" (the way I understand things) instead of newer more automated methods.