Garageband projects won't upload to iCloud
I've recently been using Garage band and have save a number of projects to iCloud so I can pick them up and work on them on different machines.
However, after initial success, the projects are non longer uploading. I've saved then to Garageband for macOS in iCloud. On the original machine they show a small cloud icon next to them in Finder, but they never upload. There's plenty of space for them there, I'm on a fast fibre connection and all the previous projects have uploaded without issue.
How can I force an upload?
Cheers