The “You have a pre-release version” parts are true
Most of the text is currently getting triggered by using a git install rather than a released tarball. This is an area of the updates system that could be improved.
From what I recall implementing the update checker should be less quirky once we hit 3.0.0 (the code doesn’t have a sane reference as of now). My production is currently on 3.0.0-alpha.6 but it isn’t showing updates since it tries to not be naggy unless there are quite a few updates in the pipeline.
The update info only gets show if your user has the admin role. So fixing it hasn’t been a high priority since a large subset of users never see it.