Chats disappearing and conversations getting scrambled after new Copilot update

I have an open case with Microsoft Support, and it remains active. Microsoft confirmed that this is an ongoing service-related issue affecting multiple users. They advised that a permanent fix requires backend changes, but I continue to experience these issues and have not yet received confirmation that a fix has been deployed.

Refreshing the page has occasionally brought missing messages back in my case. I have also had somewhat better results by keeping only one Copilot session active and signing out before switching browsers or computers.

I would also avoid switching browser tabs during an active Copilot conversation whenever possible. In my testing, switching tabs has repeatedly caused recent Copilot messages to disappear. However, these are only observations and temporary workarounds, not confirmed solutions. The problem has also occurred without a tab switch.

I recommend taking screenshots of important responses immediately because messages may disappear and sometimes reappear later. Unfortunately, the issue remains unpredictable.