Microsoft has mitigated a known issue causing the Windows 10 May 2020 Update to be blocked from rolling out to some Microsoft Surface devices. The issue was causing errors or unexpected restarts on some Surface devices that have more than one Always On, Always Connected capable network adapters. Microsoft resolved the issue today with the release of the KB4557957 cumulative update for Windows 10 2004 as part of the June 2020 Patch Tuesday. The safeguard hold preventing Surface devices from upgrading to the latest Windows 10 release is estimated to be fully removed within the coming weeks.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-fixed-bug-blocking-windows-10-2004-on-surface-devices/