We're usually pretty quick to point out when things are broken. And so we should strive to be just as fast to point out when they're fixed. And while I don't know exactly when Instagram posts began sharing properly on Google+ — chances are it's been working longer than I realize, a fact someone surely will point out in the comments, thus proving my point — but it's a welcome change, for sure.
Of course, now we can (and should) remind ourselves (and Facebook) that while there are buttons in the Instagram app to easily share with Facebook and Twitter, you'll have to separately share the link to the Instagram post on Google+.
One thing at a time, I suppose.