If they don't view G+ as an important product and it's about to be shut down, it wouldn't surprise me if they set an aggressively low quota on its compute and storage resources. Google internally bills teams and product groups for services they use, AFAIK.

Throughout the years I’ve seen most if not all Google services have glitches or go down completely.

Google has all sorts of awesome things, but fault proof hardware is not achievable in the real world.