Note that the release notes for 1324 say that from now on they will sometimes ramp up rollout slowly and not everyone may get new updates on the first day for some releases. In principle this is a good thing to minimize impact of any issues before they hit everyone.
It’s not quite clear though in the release notes if this means that this is the case already now with the update from 1311 to 1324, or only after 1324. Maybe they have just forgotten to turn on the 1324 update
Are you still unable to update automatically? If not, this is unsurprising, as the team has paused a partial rollout while we work to resolve several bugs.
There is no functional or performance difference between these two builds, and you can expect the next build to automatically update as expected upon release.