At the moment that app-id is used in the Link by using "Email-A-Link"-OOTB-Functionality.
For now, thats an issue if users, which do use different apps, use that functionality. Because if the colleague (other user) have no access to the app, but access to the record, he is not able to access the record with the provided link in the email.
Idea: don't put the app-id in the link, I did try tu use the link, without an app-id, and its working anyway and its opening the record with the ap, which is already used in the window/browser...