iOS 12.1 beta 3 comes one week after Apple seeded the last beta build to developers. A bug was causing some of these models to hook up with a slower 2.4GHz Wi-Fi network instead of a faster 5GHz signal.
iOS 12.0.1 should now be available for all eligible devices as a free over-the-air update.
Thankfully, Apple's new iOS 12.0.1 update has now been released, addressing the issue with a 104MB download that "fixes an issue where some iPhone XS devices did not immediately charge when connected to a Lightning cable". "For example, the iPad keyboard will now show the ".?123" key in its original place; some apps which were having problems showing subtitles should also now be fixed.
Less than a month after releasing iOS 12, Apple has begun rolling out the first update for the new version of its mobile operating system in order to address a few notable issues that have arisen since launch.
It's worth noting that anecdotal user reports suggested that this software bug could be addressed by a full iTunes restore without a backup.
Your iPhone or iPad should automatically offer the new update, but you can also trigger it manually by heading into Settings, choosing General, and then Software Update.