I've heard repeatedly voices against "invalidated" signal being emitted from TpProxy::dispose. We should reconsider this in 'next'.
My personal opinion:
1) yes it should have never been like that.
2) sadly, even in next, that a too subtle behavior change that will lead to unexpected bugs in our apps and even in tp-glib itself. We have no way to "grep" all places where we depend on that behavior...
Oops was already reported
*** This bug has been marked as a duplicate of bug 22119 ***