Wonderful mod. really handy in a stretched out megabase.
The bug I noticed is, that when clicking the shortcut, in the List of vehicles, which is written to the chat, the map pings don't do anything. I would have expected, that clicking them would open the map in that specific location, like it does when clicking a map ping, created with CTRL+ALT+LMB (which does work - I checked).
I think you're right, I think it'll be a problem for any surface other than Nauvis, so that'd also impact mods like Space Exploration (or Factorissimo but if you can't find your car inside a Factorissimo building I don't know what to say)
The Wiki at https://wiki.factorio.com/Rich_text says I can include the surface in the tag, and that ". When the player is on another surface than surface, clicking the tag does nothing. Mods must handle this case with on_player_clicked_gps_tag" so I will try just adding the surface to the GPS tag to see if that works.