Photos in iPhoto assigned to multiple places

I have photos in iPhoto that appear to be linked to two different places. When one place is modified or deleted, then the other place data for the photos is removed.

To illustrate I'll use simplified labels.

I have a place that can be found in Window > Manage My Places that I will call Place A. Place A has a large radius—the size of a small town.

There are also other places that appear in Manage My Places (called Places B, C, D, and E) that fall within the circumference of Place A.

Although Place A appears in Manage My Places, there are no photos explicitly assigned to Place A. There is not a single photo in my Library that displays Place A in the map on the Info panel when the photo is selected. Place A also does not appear as a pin on the Places map although it does appear in the Places drop-down menu.

There are some events in my Library that contain photos assigned to Places B, C, D, and/or E. When one of those events is selected in Events view, the map in the Info panel shows the location of the place(s) in that event, but the name it displays is "Place A." In the same way, if I open that event to see all of its photos, the map in the Info panel shows the proper location(s) but with the name "Place A." When I select one photo in the event the map displays the correct name.

In Manage My Places, if I delete Place A, move its location, or change its radius, then all the photos assigned to Places B, C, D, or E switch to Place A. That means that if I select any of those pictures at that point, the place information in the Info panel shows both the name and location of Place A. The only thing I can do to Place A that does not change the place data for other photos is to rename it.

I want to eliminate Place A from Manage My Places, but I cannot do that without removing the place data for hundreds of photos.

My current workaround is that I renamed Place A to "Place A [DO NOT MODIFY OR DELETE]" as a reminder to myself.