Bug in Gtalk And hangouts

Google's Hangouts/GTalk messaging system is currently experiencing a glitch where messages are being incorrectly delivered to unintended recipients.
Several users have found that since around 4pm  this afternoon, messages sent over Google Hangouts and GTalk have been sent erroneously to the wrong recipients.
There appears to be no pattern to who is receiving the messages by mistake, or who the glitch affects.

including those that have not yet switched over to Google's new Hangouts platform. Messages appear to be visible on the mobile version of Hangouts. There is no indication that the messages are being received by a third party.