Master Slave Replication Issue

[dennis nalog]

Hi,
We are using Solr 7.1 and are solr setup is master-slave replication.
We encounter this issue that when we disable the replication in master via UI 
or URL (server/solr/solr_core/replication?command=disablereplication), the data 
in our slave servers suddenly becomes 0.
Just wanna know if this is a known issue or this is the expected behavior. 
Thanks in advance.
Best regards,Dennis