[Note: ticket is probably related to https://forum.mattermost.org/t/urgent-users-become-logged-in-to-another-user/6184 where users log in as the wrong user]
Users are seeing messages that people sent to someone else.
Steps to reproduce
Mattermost Version: 5.3.1
Database Schema Version: 5.3.0
User A logs in, suddenly becomes User C instead.
User A sent message to User B.
User B sees this message under User C’s direct messages, but in the chat itself it still shows as from User A.
User B replies to User C with a test message.
User C sees the test message AND the original message which User A sent to User B.
Message should only go to users who they were sent to.