Thank you for taking the time to visit the Community to report this issue, although I apologize that you're experiencing this trouble.
First, If you haven't already and open Quicken and go to the Help menu > Report a Problem. There have been ongoing issues with syncing. This report will help contribute to the research of these issues.
Do you use the mobile or web app at all? If not, can you confirm if the option to sync to the mobile/ web is on. To confirm, please navigate to Edit > Preferences > Mobile & Web, there will be an on-off toggle. Can you also navigate to the One Step Update settings and confirm if sync to the cloud is selected there?
If either of these options is enabled please disable them and see if this resolves the issue. If this does resolve the issue, it's possible that you may need to move forward without syncing to the cloud or mobile app until the issue has been corrected.
I hope this helps to clarify.