Sleeping Sessions with NULL sql_text and sql_command

I'm monitoring my SQL Server environments (local setup, various versions like SQL Server 2017, 2019, 2022) and frequently encounter sessions that appear as sleeping but have sql_text and sql_command as NULL or empty.

I've attached an image (refer to your screenshot here) that illustrates an example. In it, session_id 73 has a 'sleeping' status, but the sql_command and sql_text columns are empty, while database_name is 'master'. The duration of this idle session is already quite significant (42 seconds in the example).

The script I use to gather this information is based on SQL Server DMVs and is quite similar to what tools like sp_whoisactive provide. The relevant part of the script that attempts to retrieve the query text is as follows:

SELECT
    RIGHT('00' + CAST(DATEDIFF(SECOND, COALESCE(B.start_time, A.login_time), GETDATE()) / 86400 AS VARCHAR), 2) + ' ' + 
    RIGHT('00' + CAST((DATEDIFF(SECOND, COALESCE(B.start_time, A.login_time), GETDATE()) / 3600) % 24 AS VARCHAR), 2) + ':' + 
    RIGHT('00' + CAST((DATEDIFF(SECOND, COALESCE(B.start_time, A.login_time), GETDATE()) / 60) % 60 AS VARCHAR), 2) + ':' + 
    RIGHT('00' + CAST(DATEDIFF(SECOND, COALESCE(B.start_time, A.login_time), GETDATE()) % 60 AS VARCHAR), 2) + '.' + 
    RIGHT('000' + CAST(DATEDIFF(SECOND, COALESCE(B.start_time, A.login_time), GETDATE()) AS VARCHAR), 3) 
    AS Duration,
    B.command,
    A.session_id AS session_id,
    TRY_CAST('<?query --' + CHAR(10) + (
        SELECT TOP 1 SUBSTRING(X.[text], B.statement_start_offset / 2 + 1, ((CASE
                                                                          WHEN B.statement_end_offset = -1 THEN (LEN(CONVERT(NVARCHAR(MAX), X.[text])) * 2)
                                                                          ELSE B.statement_end_offset
                                                                      END
                                                                     ) - B.statement_start_offset
                                                                    ) / 2 + 1
                     )
    ) + CHAR(10) + '--?>' AS XML) AS sql_text,
    TRY_CAST('<?query --' + CHAR(10) + X.[text] + CHAR(10) + '--?>' AS XML) AS sql_command,
    FORMAT(COALESCE(B.cpu_time, 0), '###,###,###,###,###,###,###,##0') AS CPU,
    FORMAT(COALESCE(B.granted_query_memory, 0), '###,###,###,###,###,###,###,##0') AS used_memory,
    'KILL ' + CAST(A.session_id AS VARCHAR(10)) AS kill_command,
    (CASE 
        WHEN B.[deadlock_priority] <= -5 THEN 'Low'
        WHEN B.[deadlock_priority] > -5 AND B.[deadlock_priority] < 5 AND B.[deadlock_priority] < 5 THEN 'Normal'
        WHEN B.[deadlock_priority] >= 5 THEN 'High'
    END) + ' (' + CAST(B.[deadlock_priority] AS VARCHAR(3)) + ')' AS [deadlock_priority],
    A.[status],
    A.[host_name],
    COALESCE(DB_NAME(CAST(B.database_id AS VARCHAR)), 'master') AS [database_name],
    COALESCE(B.start_time, A.last_request_end_time) AS start_time,
    W.query_plan
FROM
    sys.dm_exec_sessions AS A WITH (NOLOCK)
    LEFT JOIN sys.dm_exec_requests AS B WITH (NOLOCK) ON A.session_id = B.session_id
    JOIN sys.dm_exec_connections AS C WITH (NOLOCK) ON A.session_id = C.session_id AND A.endpoint_id = C.endpoint_id
    LEFT JOIN msdb.dbo.sysjobs AS D ON RIGHT(D.job_id, 10) = RIGHT(SUBSTRING(A.[program_name], 30, 34), 10)
    LEFT JOIN (
        SELECT
            session_id, 
            wait_type,
            wait_duration_ms,
            resource_description,
            ROW_NUMBER() OVER(PARTITION BY session_id ORDER BY (CASE WHEN wait_type LIKE 'PAGE%LATCH%' THEN 0 ELSE 1 END), wait_duration_ms) AS Ranking
        FROM 
            sys.dm_os_waiting_tasks
    ) E ON A.session_id = E.session_id AND E.Ranking = 1
    LEFT JOIN (
        SELECT
            session_id,
            request_id,
            SUM(internal_objects_alloc_page_count + user_objects_alloc_page_count) AS tempdb_allocations,
            SUM(internal_objects_dealloc_page_count + user_objects_dealloc_page_count) AS tempdb_current
        FROM
            sys.dm_db_task_space_usage
        GROUP BY
            session_id,
            request_id
    ) F ON B.session_id = F.session_id AND B.request_id = F.request_id
    LEFT JOIN (
        SELECT 
            blocking_session_id,
            COUNT(*) AS blocked_session_count
        FROM 
            sys.dm_exec_requests
        WHERE 
            blocking_session_id != 0
        GROUP BY
            blocking_session_id
    ) G ON A.session_id = G.blocking_session_id
    OUTER APPLY sys.dm_exec_sql_text(COALESCE(B.[sql_handle], C.most_recent_sql_handle)) AS X
    OUTER APPLY sys.dm_exec_query_plan(B.plan_handle) AS W
    LEFT JOIN sys.dm_resource_governor_workload_groups H ON A.group_id = H.group_id
WHERE
    A.session_id > 50
    AND A.session_id <> @@SPID
    AND (A.[status] != 'sleeping' OR (A.[status] = 'sleeping' AND A.open_transaction_count > 0))

My main questions are:

• What exactly causes sql_text and sql_command to return NULL for sessions that are in a 'sleeping' state, especially when the open_transaction_count > 0 condition indicates an open transaction?
• How can I more effectively investigate the origin of these NULL sessions?
• Is there a way to retrieve the query text or identify the operation that left the transaction open, even if sql_handle or most_recent_sql_handle are no longer in the cache or don't point to anything valid?
• Does this usually point to an issue with how the application manages its connections and transactions (e.g., missing COMMIT/ROLLBACK in try-catch-finally blocks), or can it be an expected behavior in certain SQL Server scenarios?