Are the maps inserted as objects? That's the only way I can think of that double clicking the map will open it for editing if it's not stored by reference. As a work around, you might want to try storing them by reference and see if that makes a difference. You can still double-click the file to open and edit it when they are pictures stored by reference instead of objects.
A knowledge base article lists OLE as a feature "to be deprecated", in future versions, so you may not want to use inserted objects in your container fields anyway.
Thanks for posting.
I was able to reproduce this behavior as well but, as PhilModJunk pointed out (thanks!), OLE support is to be deprecated.