Sorry it took so long. First I had to wait for the peace treaty to wear off. Then when I did declare war 1 city had no defenses, then the next went into rebeling. So here is one with 10% defenses. However to my surprise the Ram had City Bombard button!
I have no idea why or how its back but thank goodness it is. I would still be on the look out for the bug. But I suspect maybe it was a problem with cities displaying a defense when they really have 0%.
Sorry I could not provide you with a save. But its apparently not broken now.