jm_ on #debian kindly pointed out this reference: http://blog.mycre.ws/articles/bad-google-repository-signatures/
Which says that: 1. it's google fault; and 2. they might fix the symptoms, but they won't fix the underlying cause. It doesn't suggest any workaround except to re-run apt-get update. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org