Replication Monitor Missing Subscriptions in Watch List In Replication Monitor, for one of our publications (transactional replication), none of the subscriptions are showing up in the Subscription Watch List. This is new behavior that just started recently.

The other publications associated with this distributor don't exhibit this behavior, the subscriptions are visible under the Subscription Watch List tab.

I can reproduce similar behavior using the Sp_replmonitorhelpsubscription SP. When executing this using the @publisher that is not returning results in the Replication Monitor, no results are returned. But when using the @publisher that do show subscriptions, results are returned.

I've confirmed in the subscription database for this affected publisher that transactional replication is functioning as expected, commands are being delivered, row counts are in sync.

Is there anything that can be done to get the subscriptions to appear again for the affected publisher? The only thing I can think of doing is deleting the subscription and publication and starting over, since some metadata must be missing, but that requires a downtime and seems unnecessary.

Version: Microsoft SQL Server 2008 R2 (SP2) - 10.50.4000.0
Update for resolution if someone is having similar situation.
I faced similar scenario where I could not get subscription agent list pulled up when launched replication monitor neither I could get the result from Sp_replmonitorhelpsubscription and the query kept on running without result. When checked currently executing query, all the  distribution agent jobs were being blocked by couple of pull subscription distribution agent also causing issue for other distribution agents jobs and couldnot pull replicated commands. I stopped and restarted those 2 head blockers distribution agent jobs that released the rest of distribution agent jobs. This resolved the issue with subscription agents not being showed up on the replication monitor.