Multi Instance Deployment - notification missing


Hi, I’m testing a Rocket Chat multi-instance deployment on single node.
Everything run on the same server (http Server, RC instances and mongodb replica set).
I know that my deployment solution is not compliant to standard, but it works!
The only mistake that I observe is the instances synchronization ( “is typing…:” notification is missing).

Scenario that produces the mistake:
User A is connected to instance1
User B is connected to instance2
A writes and sends a direct message to B
B receives notification on Direct Message label and open the room
B starts to write the response for A.

Scenario result description
During B typing, A doesn’t see the “is typing…” notification above the room input text field.
The browser notifications don’t show, too.
If both users are connected on the same instance all works!
Could anybody help me to understand where I’m making a mistake?

Environment description
S.O.: Centos 7.5

Front End/balancing: HTTP Server Apache 2.4

RocketChat Instances:

MongoDB: (Primary) (Secondary) (Secondary)