Same problem here. Notes on my 2017 devices (iMac and iPad Pro) sync to iCloud. All other devices (MBP 2012, iPhone 6s+) do not reflect any changes I make or newly created notes back into iCloud.
Here are the notes that, when created on my older devices, do not sync to iCloud:
If I create these notes on an older device, they don't sync to iCloud. Super frustrating.
- Notes with Checklists
- Notes with Scanned Documents
- Notes with Tables