GoldenGate: DML data did not replicate into Target Oracle database automatically

Hello,

I setup GoldenGate v12.1.2.1.8 at Source (SQL Server Windows 2012R2) Target (Oracle12c  v12.1.0.2.0 pluggable database).

Initial Load was done, and row counts between Source/Target databases are in sync.

I created Extract EXT1, PUMP1 at source database, Replicate REPL1, REPL2 with checkpoint table at target database.

Problem:

After Extract and Replicat were started, 

I saw data changes at Source database, but, I don't see DML data replicate to Target database automatically, unless if I restarted Replicat and could see new data applied to Target database.

After a while, I saw data changes at Source database again, but, I don't see DML data replicate to Target database automatically unless if I restarted Replicat could see new data applied to Target database.