Seems the pattern matching on the reboot command only check the first few characters...
"ciscoasa# session sfr
Opening command session with module sfr.
Connected to module sfr. Escape character sequence is 'CTRL-^X'.
(none) login: admin
Password:
Last login: Thu Oct 15 16:24:24 GMT+7 2015 on pts/0
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Cisco is a registered trademark of Cisco Systems, Inc.
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Cisco Linux OS v5.4.1 (build 12)
Cisco ASA5506 v5.4.1 (build 211)
>
> system reboot
This command will reboot the system. Continue?
Please enter 'YES' or 'NO': yah
Invalid input
This command will reboot the system. Continue?
Please enter 'YES' or 'NO': yesterday
Broadcast message from root@(none) (Thu Oct 15 16:35:34 2015):
The system is going down for reboot NOW!
> Remote card closed command session. Press any key to continue.
Command session with module sfr terminated.
"
