"User is typing..." status missing or not working all the time in a E2E private chat

Description:

Using a private E2E chat there is no visible feedback when user is typing back. Sometimes it just aprears moments before the message is posted, sometimes a few seconds while the user is typing, but most of time it is missing. This happens on new and old/existing chats

Steps to reproduce:

1. Other party starts to type
2. Message is posted but no status while tryping

Expected behavior:

Expected to see "Username is typing..."

Actual behavior:

There is no visible status of when user is typing or not

Server Setup Information:

• Version of Rocket.Chat Server: 3.7.0
• Operating System: Linux
• Deployment Method: docker
• Number of Running Instances: 1
• DB Replicaset Oplog:
• NodeJS Version: v12.18.4
• MongoDB Version: 4.4.0

Client Setup Information

• Desktop App or Browser Version: App v. 2.17.9
• Operating System: macOS Catalina

Additional context

This is not a problem with regular none E2E chats

Relevant logs:

The issue names no files, tests, or entry points. Start by reproducing typing in a private E2E chat and compare it with a regular non-E2E chat. Done means the other participant consistently sees “Username is typing...” while text is being entered, before the message is posted.