Some of the common bugs in the first release of Beta 3 are:
1. When you press on the volume keys, it triggers silent mode.
2. Control Centre does not work properly.
3. The iPhone would freeze often.
4. Rotation would not function properly
5. LTE and WiFi issues during a FaceTime Call.
6. When you press the volume buttons to take a picture in the camera App, the Camera interface is blurred.
So Apple had to fix a few of the above major bugs and re-release Beta 3.