It looks like the crash stats also shot up around the same time (11/17) at bug 1676102, which is Mac-specific.
Bug 1644249 Comment 5 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
It looks like the crash stats also shot up around the same time (11/17) at bug 1676102, which is Mac-specific. Note, though, that they didn't shoot up on trunk, but only on beta (and maybe also release). So possibly a change to infrastructure is responsible (if only indirectly).