There should not be a outcallcontext (what is that by the way ?) appended to the caller_id_number.
Something must be wrong in your config.
I tend to agree with David on this. Please use pastebin.freeswitch.org and drop us a debug log of a call that has this symptom. Use "FreeSWITCH Log" for the syntax highlighting and reply to this thread with the pb link...