I created a To Do note on my phone (Android) 2 weeks ago. I also viewed the note with a web browser (via notebook.zoho.com) on my computer. Five days later I edited the note and added some more list items on my phone while not connected to WiFi. My phone may have had a cell data connection at this time, or it may have had no Internet connection, I'm not sure. A small sync icon with a slash appeared at the top corner of the note in the notebook grid view:

At first the new/edited version of the note did not sync to my computer (web browser), and I had to edit it on my phone a couple times before if finally synced and I was able to view the latest version on my computer. However, the strange icon is still there (on my phone only, not in the web browser), and I cannot figure out what it means or how to make it go away. What does the icon mean? Should I be worried? Is there a way to make it go away?

Thank you.