Hi, i also encountered this problem. I maked sure the cloud driver on ios and macOS is open and same account is logged in. But just some notes are synced on my iphone and mac, when i updated note on my iphone, it does not appear on my mac. In addition, the context updated on my mac also can not sync to my iphone.
Therefore, partial content is respectively on mac and iphone. 
Can you give me some help?
Usually the sync is just taking a while. What I would recommend is this:
See if it all syncs up. If not, let me know.
Sorry for the trouble.
Kind regards,
Drew
Hi, thanks for your reply, i followed your instruction and waited it to sync overnight. When waked up, i got the whole notes on my iphone and mac, so great!!
I like agenda, hope it become better and better. 
Glad it worked out in the end. Hopefully now the sync will be fast.