Illustrator Document hasn't saved most recent changes OneDrive

So I've been working on a large illustrator file for months and I have been saving it to OneDrive with no issues. This morning I worked on it for a couple of hours and saved it, before returning to a different pc a while later and when I open the file the changes I made aren't there. In the files version history the last time it says it has been saved was 2 days ago which was the last time I saved before this morning. Why has this happened and is there anyway to prevent it in the future or recover the lost work?
Thanks