Apple removes iOS 12 Developer Beta 7 OTA update due to performance issues
After getting multiple reports on the performance issues, Apple was forced to pull iOS 12 Developer Beta 7 OTA update. At the time of writing, the OTA software update is no longer available. However, determined users can still update via the direct download option from Apple's developer site.
The performance issues were rendering devices useless. The sluggish performance affects app launches making apps to take ten times longer than usual to load when launched and the lock screen and system animations appeared to be frequently hung.
It appears that for some users the performance issues disappear after five or 10 minutes of using the iPhone, and performance starts to normalize. However, most users the issue never disappears. There have also been reports of other issues, such as apps freezing, Notification Center freezing, Lock screen freezing, and in-app functions refusing to load.
Apple was supposed to release the Public beta of iOS 12 this week, but that may be delayed until these performance issues are addressed in an updated release.
For now, if you avoided the OTA software update, it looks like that was a good idea. If you are one of the unfortunate souls that have the update, then hopefully Apple will soon release an update that will address this issue. If you cannot wait for Apple, then the only surefire way to fix things is to flash a restore image.