I created two apps that uses Outlook and Office 365 Users as connections and embeded it in our SharePoint.
I then created a test user and gave that account access to the SharePoint and shared both apps with that account. I was able to view and use the embedded apps in SharePoint. I then removed the test user from having access to the apps in Powerapps. I signed out and back into windows as the test user. When I go to the SharePoint on Chrome I can still see the apps and use them even though the test user dooes not have access to them in Powerapps. When I use the Edge browser, the test user has access to only one app and the other app says that I don't have access to it. In Powerapps, as the test user, I dont have these apps listed anywhere, not under share with me or apps in my org.
Why can my test user still access these apps on SharePoint when I'm not sharing access with the test user anymore?
Do you mean that the test user could still access this embedded app even when you remove the access permission for him to this app?
I think this issue may be related to the cache of your Chrome. Please consider take a try to clear cache of your Chrome, then use the Test account to access the SP Site Page, check if the isue is solved.
If the issue still exists, please consider take a try to submit an assisted support ticket through the following link: