I'm wondering whether this is a pure coincidence or on purpose (by BWauths) or by some other yet to be found reason?
I guess I found the answer by looking at another spike (2014-11-01)..
Since these relays came back altogether (they are a group after all) and probably had no measurement within the last 3 days they are unmeasured.. that would make sense.
I'm wondering why the second group has no exit flag https://atlas.torproject.org/#search/TorExitNode
Do exits have to have a measurement and/or certain uptime besides the 2 out of 3 ports rule (80,443,6667) to earn the exit flag?