Hello 
One of my projects keeps showing this You have unsaved changes dialogue (As if I were offline).
I can open and sync any other project but for some reason, when I want to close this project, the dialogue keeps showing up.
I’m using the desktop app and when I make changes, they do reflect in the webapp. So not sure what’s going on.
Anyone knows how to fix this?
Just close it and reopen. Since you can verify the changes are saving, you won’t lose anything. Probably just a glitch.
Hey Bernado 
Gleb’s advice here is spot on! Syncing offline changes is covered in detail in ‘Can I work offline with Figma?’ and if your work is updated in the Browser, you should be all good to restart the Desktop App to clear that warning.
If you continue to see this warning after restarting the Desktop App, or in both the Desktop App and Browser, you can flag it with the Support Team by using the ‘?’ to ‘Get help’ and we’ll be happy to troubleshoot with you.
I have the same issue and closing it and reopening it does not work. The same issue comes up. And on desktop it prevents the project from loading. On browser it opens but the notification is still there.