I clicked a jump to parent link that was for a message a couple days in the past. This worked fine. While I was there, a new message came into the room. When I clicked the down arrow to go to the bottom it scrolled to the bottom and I saw the new message, but just prior to the new message was a bunch of old messages and not whatever was actually prior to the new message.
Clicking to another chat and clicking back fixed this. But I was able to reproduce twice.
If no new message comes in during this time, then the issue doesn’t seem to exist.