I had a situation where I lost significant progress on a document. I'm not sure if it is a common situation but I think there is a way to avoid it for others in the future.
In my case, the launcher quietly stopped sending updates to LW while I was working on a brief and had the document open for several days (probably not a good practice and I will avoid it in the future). I was unaware of the launcher glitch and I saved and closed the file. Then, when I reopened the file from LW, it downloaded and opened the last uploaded version from more than a day earlier -- not the most recent version I had saved before closing the file. This action of reopening the file from LW overwrote the locally stored version of the document with the old version from the cloud. As a result, all of the work done during the time the launcher was not uploading was lost. I did get lucky, however, because I had Apple time machine going and was able to restore a fairly recent version of the locally stored file, so I only lost 1-2 hours of work.
I'm not sure why the launcher stopped uploading or if that has been a problem for others. It is working fine now. The problem is I didn't
know
it stopped working, which led me to inadvertently overwrite the file and lose valuable work.
My proposed solution to this kind of problem is to have the launcher prompt the user after X minutes of no upload activity when the user has one or more LW documents open. The X value could be an adjustable user setting so the prompt doesn't get too frequent/annoying. I see at least two benefits of a prompt: (1) if the user has been saving the document(s) frequently, the prompt can clue the user in to the fact that something might be wrong with the upload/backup process before too much time passes, and (2) if the user has not been saving frequently, it can at least remind the user to save the file(s), thereby prompting an upload to LW and reducing the risk of losing valuable work.
On this note, I am in favor of LW continuing to create a new version of a document every time the user saves a file, especially after this experience. I know the many versions can be cumbersome, but I am hoping LW will take my suggestion about cleaning up the viewing options for that. (see https://lexworkplace.canny.io/feature-requests/p/avoid-multiple-versions-with-every-save)
Until there is a prompt, I recommend checking the launcher window regularly to make sure it is working. If you put many hours into a single document, I definitely recommend confirming successful upload before you close the document. I also recommend having a redundant backup like time machine in case something weird happens like it did to me.