Having a problem with replicating a database between two servers, both running SQL 2012. We have a table where each site that stores the database updates a record every minute with the current time stamp. This way either location can see whether sync is up to date.
The problem we've got is after so many months of this working perfectly one of the sites (subscriber, not publisher) will stop transmitting this change to the other. The subscriber still updates this record but this change never gets sent to the other site. Other changes do, so sync is still up. The publisher's change and any other subscriber's changes to its own record gets sent across. Nothing appears in logs or the conflict logging table for any problems with this table. It just doesn't update.
If we validate the subscription it'll see the change and update, but then will again not take any further changes to the records unless validation is again done. If we re-push the database then the new subscription works fine and doesn't show any of these problems. It seems to be something tied to this one particular subscription/database. Possibly related but Management Studio's replication monitor reports the data flow as being around .01 rows per second, though checking activity it's frequently downloading/uploading or waiting. We can't repush/reinitialize due to the importance of these systems staying up.