This is the information that was in the dashboard for a day or so and to me has the same issue, so I am surprised that it is still there. On an MX75 that I have in routed mode with most ports set to access VLAN x, I have:
Device Name
Port 6 via (MX name)
On the details tab I have:
Wired connection
Security gateway (MX name)
Port 5
This mismatch is exactly why the web page was pulled and it appears to have not been fixed in the app...