Two circuits for one domain (Circuit visualizer sometimes shows the "wrong" exit node)
Making an arbitrary number of new circuits (either with the new identity button or when the Tor client creates circuits while browsing) eventually causes the circuit view in Torbutton to show the wrong exit node.
I have noticed this in Tor Browser 5.0.3 through Tor Browser 5.0.7
When testing this I found that the number of new circuits that are needed to reproduce this varies. Sometimes it happened first time I visited check.torproject.org, other times I spent 10-15 minutes creating new identities.
A screenshot can be found on stack exchange. https://tor.stackexchange.com/questions/9460/why-does-torbutton-circuit-view-not-consistently-show-the-correct-exit-node