SQL Server Log Reader Agent while trying to add node in p2p Replication
Adding the resolution for the benefit of anyone who faced this issue on SQL 2012:

We engaged MS support on this. Apparently their stored procedure "sp_dropsubscriber" misses some tables sometimes. In our case, this entry was not deleted from table MSnosyncsubsetup. Once they found this out after few hours of analysis, a backup was taken and the row related to new subscriber was deleted.
This fixed the log reader and replication hummed along properly.