There was an earlier post with this issue that I can't add a comment to because it was "resolved" by a moderator saying to check with the carrier....that of course did not work.
But.......
The beta appears to have fixed the dual sim issue in OneUI 6. Previously if one sim was selected as primary, the phone would automatically swirch the secondary sim to primary if a message was received. This caused issues as my secondary sim is voice only and my phone would constantly lose data connection. I'm pleased to report that this behavior has stopped after updating to the beta.
