I have a Catalyst 6509 with Supervisor Engine 720. It is just newly upgraded to IOS version 12.2(33)SXH1, ADVANCED ENTERPRISE SERVICES SSH.
I telnet to the switch and then establish an SSH connection to another router, as follows:
C6K_Switch#ssh -l testuser 172.28.14.100
After authenticated, my session hangs. Hitting Ctrl+Shift+6,X didn't suspend the session. I have to open another telnet session to the switch and clear the line.
I used to have no such issue when the switch was on the previous IOS version 12.2(18)SXF12a.