I did not know that. This is a nice mashup of “there are two sides to every story” (there are valid reasons for holding opposing opinions) and “two sides of the same coin” (different but closely related features of one idea). Obviously “two sides” share each idiom, causing the confusion. A big thanks to Curious Steph for hearing this one and sending it in. As she said, “the sides got left out, coining a new story!”. Check out Steph’s blog at curioussteph.com.