Potencial BUG in DIAL() command by using "ring-timeout&


I have a problem by using Dial() comand and seting “ring-timeout” for more then 2sec. It’s simply hangs up channels of TDM400 FXO ports (FXS signaling). To be more specific: I have TDM04B Zaptel analog phone card, currently I’ve connected 1st and 2nd line to our comnaye’s intire PBX. I’m trying to redirect incoming call from 1st FXO line to another extension (let’s say Ext:221) by using 2nd port of TDM400 card. I’m using Asterisk v1.2.1 based on Debian Linux.
Comand of extension.conf looks ike this: exten => 221,1,Dial(Zap/2/221,5) Call rings to designed Extension (221), but never ends (I’m not picking up the phone), even I hang up the first initiated line (1st port of TDM400)… Time out of >3sec do not works, but less then 3sec semms like work OK. Is it bug of Asterisk, or I doing something wrong? By the way debugging (-cvvvv) shows, that call beeing initiated, something like “Zap/2/221 | 5” and that’s it… both channels are busy till Asterisk will be restarted…