Hello @James Nail
Thank you for
reaching out on the community and telling us about your issue. I do apologize for the issue you're having. It sounds like you've already taken a couple of steps here to try getting it validated. Another thing I would attempt here would be to try to duplicate the budget then attempt to resync it. To do this if you go to the planning tab and in the top left select the cogwheel you'll get a dropdown with the option to duplicate the budget. Once it's duplicated it double check it's correct then select the original budget and select the cogwheel again to delete it. Once that's been done try resetting syncing with the cloud again.
I'm not sure if this will fix it another thing would be to try resetting the cloud after duplicating the budget as well. To do this you can navigate to edit > Preferences > Mobile and web > reset your cloud data.
Once you've given this a chance let us know if it helped. If not we'll see what we can try next.