First of all, a huge thank you to 404 for quickly reporting the cloud save bug. We really appreciate the help.
We have been actively working to bypass the synchronization issue. With this latest small update, the cloud save system should now be working properly. We implemented a fix that should ensure your save data migrates and backs up without any more errors.
Since save files are incredibly important, please let us know if everything is running smoothly for you now, or if you still encounter any strange behavior. We will keep a close eye on your feedback.