GPRS issue after idle

Hello,I got everything up and running. Including EDGE data. The throughput of the data from the osmo-sgsn is pretty good. But recently I have spotted a problem with the SGSN. The sgsn loses the phones SNDCP entity after idling or making a phone call. Please see the log from the sgsn http://pastebin.com/2W9dZdvW