[Urgent] User messages shown to wrong user

[Note: ticket is probably related to https://forum.mattermost.com/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
Database: postgres

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.

Expected behavior

Message should only go to users who they were sent to.

Observed behavior


Hi @Camille

The information are requested here will also be helpful in this case.