The System Info -> Software -> Applications list is not a complete check on 64/32-bit. I believe it checks the main executable inside each app bundle and reports that. But it does not check the other executable components inside the app bundle. So you can have an app which is mixed 64 and 32-bit, but reported by System Info as 64-bit.
When you start such a mixed app for the first time, macOS will give its warning about future compatibility.