Users getting session timeout and don't recieve messages/sent messages are greyed out

Description:

Diverse users are getting in different times a session timeout although expiration day is set to 90 days.
After reconnecting there are several problems with sending and receiving messages in direct message and channels. Occurs in web browser as well as in rc-client.

Steps to reproduce:

1. User A gets disconnected and logs in again.
2. User A sends a message to any User B.
3. The sent message is greyed out for user A/User B receives message ordinarily.
4. Now if user B sends a message to user A, he can see "User B is typing" and he gets a new message notification, but there are no new messages visible for User A in chat window.
5. Refreshing browser cache or relogin solves this bug.

Expected behavior:

• Session timeout should apply after 90 days.
• Messages should be sent and received ordinarily after session timeout.

Actual behavior:

• Users getting timeout several times a weeks.
• Sent messages are buggy after session timeout.

Server Setup Information:

• Version of Rocket.Chat Server: 0.68.3
• Operating System: Debian 9
• Deployment Method: tar
• Number of Running Instances: 1
• DB Replicaset Oplog: No
• NodeJS Version: 8.11.3
• MongoDB Version: 3.2.11

Additional context

In browser console for the greyed out message:
id=123xyz“ class=“message background-transparent-dark-hover own temp“

Relevant logs:

Couldn't lookup logs yet.

No file or test is identified in the report. Start by reproducing the reconnect sequence in the browser and inspect the console entry for the greyed-out temporary message; done means sessions follow the configured 90-day expiration and direct or channel messages send and appear normally after reconnecting.