SSMS <-> SMO Bug listing db_datareader role members

@shueybubbles Ran into this Friday night during a production deploy that re-organized permissions... Came up with a simple repro:

Try the following database:

CREATE DATABASE [Test]
GO

USE [Test]
GO

CREATE ROLE Readers
GO

ALTER ROLE db_datareader ADD MEMBER [Readers]
GO

CREATE USER [MYDOMAIN\michael.miller] WITHOUT LOGIN
GO

ALTER ROLE Readers ADD MEMBER [MYDOMAIN\michael.miller]
GO

/* Output Table formatted with GitHub Markdown below */
SELECT * FROM sys.database_principals WHERE name = 'db_datareader'

/* Output Table formatted with GitHub Markdown below */
SELECT p.name FROM sys.database_role_members rm 
JOIN sys.database_principals p ON rm.member_principal_id = p.principal_id
WHERE rm.role_principal_id = 16390

When I go into SSMS and right click on Properties for the db_datareader role, I see the following INCORRECT mappings that do not match the output of the last two queries above:

I think there may be a separate bug here, observable in SSMS but not sure what SMO calls SSMS is making (is there a way to force SSMS to log that to the telemetry window? Telemetry window doesn't have super detailed logging by default).

The SSMS "Output Window --> Object Explorer" output I get is:

[2021-01-11T11:05:14.2162761-05:00 End Query] URN:Server[@Name='---SCRUBBED---']/Database[@Name='Test']/Role 

                                   Elapsed time:10.7294 ms 

                                   Query: SELECT
                                   rl.name AS [Name],
                                   'Server[@Name=' + quotename(CAST(
                                           serverproperty(N'Servername')
                                          AS sysname),'''') + ']' + '/Database[@Name=' + quotename(db_name(),'''') + ']' + '/Role[@Name=' + quotename(rl.name,'''') + ']' AS [Urn],
                                   rl.principal_id AS [ID],
                                   CAST(CASE WHEN rl.principal_id > 16383 AND rl.principal_id < 16400 THEN 1 ELSE 0 END AS bit) AS [IsFixedRole]
                                   FROM
                                   sys.database_principals AS rl
                                   WHERE
                                   (rl.type = 'R')
                                   ORDER BY
                                   [Name] ASC

which produces the following output table:

and the SSMS "Output Window -> Telemetry" output view has:

[2021-01-11T11:05:07.7326467-05:00] sql/ssms/explorerhierarchynode/buildchildren
                                    DataModel.Action.DurationInMilliseconds = 185.0194
                                    SQL.SSMS.ObjectExplorer.Entity = Server/DatabasesFolder
                                    SQL.SSMS.ObjectExplorer.IsSqlDW = False
                                    SQL.SSMS.ObjectExplorer.ServerType = Standalone
[2021-01-11T11:05:09.2765405-05:00] sql/ssms/explorerhierarchynode/buildchildren
                                    DataModel.Action.DurationInMilliseconds = 44.0064
                                    SQL.SSMS.ObjectExplorer.Entity = Server/Database
                                    SQL.SSMS.ObjectExplorer.IsSqlDW = False
                                    SQL.SSMS.ObjectExplorer.ServerType = Standalone
[2021-01-11T11:05:11.3234256-05:00] sql/ssms/explorerhierarchynode/buildchildren
                                    DataModel.Action.DurationInMilliseconds = 3.982
                                    SQL.SSMS.ObjectExplorer.Entity = Server/Database/DatabaseSecurityFolder
                                    SQL.SSMS.ObjectExplorer.IsSqlDW = False
                                    SQL.SSMS.ObjectExplorer.ServerType = Standalone
[2021-01-11T11:05:12.6408375-05:00] sql/ssms/explorerhierarchynode/buildchildren
                                    DataModel.Action.DurationInMilliseconds = 0.538
                                    SQL.SSMS.ObjectExplorer.Entity = Server/Database/RolesFolder
                                    SQL.SSMS.ObjectExplorer.IsSqlDW = False
                                    SQL.SSMS.ObjectExplorer.ServerType = Standalone
[2021-01-11T11:05:14.2193114-05:00] sql/ssms/explorerhierarchynode/buildchildren
                                    DataModel.Action.DurationInMilliseconds = 27.0348
                                    SQL.SSMS.ObjectExplorer.Entity = Server/Database/DatabaseRolesFolder
                                    SQL.SSMS.ObjectExplorer.IsSqlDW = False
                                    SQL.SSMS.ObjectExplorer.ServerType = Standalone
[2021-01-11T11:05:16.9081278-05:00] sql/ssms/explorerhierarchynode/setupmenuparent
                                    DataModel.Action.DurationInMilliseconds = 0
                                    SQL.SSMS.ObjectExplorer.Entity = Server/Database/Role
                                    SQL.SSMS.ObjectExplorer.IsSqlDW = False
                                    SQL.SSMS.ObjectExplorer.ServerType = Standalone
[2021-01-11T11:05:16.9191466-05:00] sql/ssms/explorerhierarchynode/getmenuitems
                                    DataModel.Action.DurationInMilliseconds = 8.9941
                                    SQL.SSMS.ObjectExplorer.Entity = Server/Database/Role
                                    SQL.SSMS.ObjectExplorer.IsSqlDW = False
                                    SQL.SSMS.ObjectExplorer.ServerType = Standalone
[2021-01-11T11:05:21.8648667-05:00] /sql/ssms/dialog
                                    SQL.Dialog.Action = Invoke
                                    SQL.Dialog.Name = DBRoleProp

Start by reproducing the database setup in the issue and compare the SMO/SSMS db_datareader role-members view with sys.database_role_members. Review the SQL shown in the Object Explorer output and the DBRoleProp entry point; done means nested role membership is displayed consistently with the query results.