I've noticed that I get these kind of results also and think its boils down to the way the nodes are added to NNM (not 100% sure but have noticed this weirdness). We've got over 250 framerelay routers and I used add the router via the framerelay serial interface IP (did this since alot of our routers have address's that arent in our IP 10 space),
and when I click on the alarm instead of going to the submap of the site, it goes to the network submap of the framerelay network.. example; a cleveland router 10.100.x.x ethernet and 10.100.0.22 frame net would go to the 10.100.0.20 subnet instead of the cleveland container.
hope this helps and doesnt confuse more than you were.