OnePlus 7 and OnePlus 7T series is now receiving the OxygenOS Open Beta 14 and 4 respectively. Though the build numbers for the phones in both the series are different, the changelog is similar.

The update fixes missing contacts problem, voice input issue and more.

OxygenOS Open Beta 14 / 4 Official Changelog For OnePlus 7 / 7T Series

• System
  • Fix the problem that some software voice input cannot be recognized
  • Fix the problem of the disappearance of contacts in the address book on some devices
  • More clock style options now available in ambient display (Settings—Customization—Clock style)
  • Improved system stability and fixed general issues
  • Updated Android Security Patch to 2020.05
• Phone
  • Now you can view call recording in call history (Move to the call history, click the three-dot menu on the upper right to access the call recording)

Source: Oneplus Forum