I had the same problem. This is the fix I received from my "support ticket". I deleted as below and readded and it worked.
Thank you for contacting Appigo Support. I will do my best to assist you.
Are all of your notes currently in Toodledo?
If all of your notes are in Toodledo currently then do the following:
-Delete your Toodledo collection by swiping from left to right over the collection name
-Once the collection has been deleted, add the collection again.