Hi Lee

Thanks for posting in the Community!

You should be able to enable or disable notifications for document changes as explained in the following help article: Change Notifications Reminders and the Notifications Feed 

Change Notifications send you a notification whenever someone makes changes to a shared document.

If you did take the steps detailed in the document I linked above but did not receive any notification when a collaborator made a change to your board I would recommend that you contact our Support Team via this form and provide as much information as possible so that they can look into the matter and assist!

Let me know if you have questions!