I just had a similar issue so I'm writing here if it helps someone.
I have added a new app, filled out the form properly and after saving I got an alert that my "new app was created but some info about users not saved properly"
In the same tab I had that new app opened but when I clicked on "Apps" in App Store Connect the new app was not visible
I have navigated back (in browser) to the page where the new app was visible, and there it was. Created, but not accessible from "Apps"
After some fiddling around I have noticed that in "Testflight" tab of the new app, there was a warning (labeled with yellow triangle icon with checkmark) telling me to complete the "Test information" data. So I did that, i added Feedback Email and filled in Beta App Review Information, and saved it.
After that I went to "App Store" tab, then "App Information" (in side menu), scroll to the bottom and click on "Edit User Access" under "Additional Information". I have selected "Full Access" and saved. Then opened it again and set "Limited Access" and saved again.
After saving that, the app appeared in "Apps"
Now, I don't know what step actually did it, but my guess is that it is one of those saves, triggered what ever it needed to get the new app visible in "Apps"
There. Good luck =]