Message ordering broken in some 1:1 rooms

[kaiyou]

Description

Since upgrading to 1.1.0, multiple users report having problems with message ordering. I myself only noticed this in new private-message bridged rooms using different kinds of bridges. tulir on #riot:matrix.org reported seing this on many 1:1 rooms.

The ordering issue could be described by :

• at some point, one (a user reported seing a bunch instead) of my messages keeps being displayed as the last message(s)
• my new messages from this point are displayed in proper order, above this one
• the other person's messages are all displayed above these

Steps to reproduce

• Open a 1:1 conversation, chat a bit until you trigger the issue
• If the issue is not triggered after a few messages, open a new 1:1 conversation

I could only reproduce this once, it does not seem deterministic, or I could not pinpoint the exact trigger.

Version information

• Platform: desktop

For the desktop app:

• OS: Arch Linux (up-to-date) and Windows, both reported
• Version: 1.1.0

[jryans]

Has anyone submitted debug logs for this issue? Those may be helpful in pinpointing the cause.

[turt2live]

Duplicate of #9443