Are you receiving a pop-up each time you perform a sync?
Could you send us your diagnostic report from the device that you are having the problem with?
You can send it to me by doing the following:
-Open Todo, tap on the settings button/ Your Name
-Tap on "Information"
-Tap on "Diagnostics"
-Scroll down to the very bottom, and tap on "Email Diagnostic Report"
-Read the instructions of the popup message and tap on "Email"
-Please include the description of the problem you are having or the ticket ID of your support case
-When you are ready to email your Diagnostic Report, tap on "Send"
To fix this issue kindly verify if the data on todo-cloud.com is current and correct, once it is kindly have the app uninstalled and reinstalled on your device and test if the issue persists.