Hope you are doing well and sorry for the trouble.
Would you mind sharing the steps you are doing to share the PDFs? When the recipient views the file, you get a notification in Adobe Acrobat and an email. To view and track all the files shared for viewing, please go through the help page https://helpx.adobe.com/document-cloud/help/sharing-pdfs.html and see if that helps.
I have set it up as per instructions and I dont get a email or notification if they have made comments, I can see in notifications if I go into Acobat but thats not good enough as I cant keep checking it, also before the update I could see next to the name /initee if they had opend it or not but that seems to have dissapeared