When I start a shell session to a host over SSH, then switch it to full-screen, the app displays a narrow black bar at the top of the screen, and freezes. This happens in either orientation, however switching orientations twice after initiating the connection, prior to entering full-screen mode delays the crash.
I see the black horizontal bar at the top in VNC sessions too, which is especially noticeable in Landscape mode. However switching orientation mitigates it, and VNC hasn't crashed for me.
This is on a GSM iPhone 5S, running iOS 8.1.2, connecting to a host running Yosemite.