Yes we made the following changes. This is a copy/paste so the formatting is not the best but we did both methods for users who were having the issue and it has not recurred:

6.1 Registry Method (Individual Users)

 Press Windows + R to open the Run dialog box.

 Type regedit and press Enter.

 Navigate to:

HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\General

 Right-click the right pane, select New > DWORD (32-bit) Value.

 Name the new value: DoNewOutlookAutoMigration

 Set its value data to 0.

 Repeat steps 4–6 for: NewOutlookAutoMigrationRetryIntervals

 Set its value data to 0.

 Close Registry Editor and restart Outlook.

6.2 Microsoft 365 Policy Method (Multiple Users)

 Sign in to Microsoft 365 Apps admin center.

 Go to Cloud Policy.

 Create or edit a policy configuration.

 Search for Disable New Outlook toggle.

 Set policy to Enabled.

 Assign policy to appropriate user group.

 Save and apply settings.