Deleting one conditional tag causes another to disappear

I have a document with five conditional tags, where each tag is a different version of a product -- let's say the tags are A, B, C, D, and E for products A, B, C, D, and E.

I recently learned that Product D will be discontinued, so I've deleted all of the D-specific text, and I've also removed the tag from any text that it shares with the other products.

Now I want to delete the "D" conditional tag completely. I've selected the tag in the Conditional Tags pod, clicked Delete, and then clicked OK. The "D" tag is removed ... but so is the "E" tag.

This looks like a bug to me, but I'm a newbie -- perhaps I made a mistake when creating the "E" tag (which I added after adding the D tag). Is this a known issue? I've searched the posts here and can't find any reports of the same problem.

Thanks!