Users overwrite each other through websocket when connection is reestablished

[JustDoItSascha]

To Reproduce
My colleagues and I discovered a bug. I open Outline and a document. Then I close my macbook. My colleague changes something in the same document. Then I open my macbook again and it seems that my outline connects via websocket to the server and overwrites the changes my colleague makes. His changes are deleted.

Expected behavior
I would assume that outline compares the versions and changes and does not overwrite things others wrote while my connection to outline was not online.

Screenshots
If applicable, add screenshots or videos to help explain your problem.

Outline (please complete the following information):

• Install: self hosted
• Version: 0.71.0

Desktop (please complete the following information):

• Browser chrome

[sncat]

As mentioned in this issue, the same overwrite seems to be happening.
When it happened in my environment, even the edit history was overwritten and no rollback was possible...

#5830