NullReferenceException with Microsoft.Data.SqlClient 5.2.0 and with event handler for Backup.PercentComplete

In our app we reference both NuGet-Packages Microsoft.SqlServer.SqlManagementObjects and Microsoft.Data.SqlClient.
We use SMO for many DB-related tasks, incl. Backup of the app databases.
We refresh the NuGet references regularly, actually we use Microsoft.SqlServer.SqlManagementObjects 171.30.0 and Microsoft.Data.SqlClient 5.1.5.
Everything worked fine until we updated Microsoft.Data.SqlClient to the actual version 5.2.0. Now our backup code throws NullReferenceException. As a workaround we switched back to Microsoft.Data.SqlClient 5.1.5.
We were able to reproduce the issue with the sample from https://learn.microsoft.com/en-us/sql/relational-databases/server-management-objects-smo/tasks/backing-up-and-restoring-databases-and-transaction-logs?view=sql-server-ver16#backing-up-databases-and-transaction-logs-in-visual-c
The only difference is the added event handler for Backup.PercentComplete. With it, the sample throws NullReferenceException when calling Backup.SqlBackup() and using SqlClient 5.2.0. The same code works fine with SqlClient 5.1.5 or earlier.

The sample is attached to the issue.
MS_SMO_BackupBug.zip

Start with the attached MS_SMO_BackupBug.zip and the linked SMO backup sample, focusing on the Backup.PercentComplete handler and the Backup.SqlBackup() call. Compare behavior with Microsoft.Data.SqlClient 5.1.5 and 5.2.0, then verify that the sample completes without a NullReferenceException on 5.2.0 while the handler remains enabled.