Crash in safefree/ssh_channel_destroy when running ssh-add --invalid in 3f115c6

I have a reproducible crash when:
- Running putty.exe from 3f115c6
- Pageant has a key loaded into memory
- ssh agent forwarding is enabled
- I run ssh-add --somethinginvalid (any invalid parameter will do)

I have a minidump of the crash but I am unsure if it will contain my keys - please advise.
