[Freeswitch-dev] FS send re-invite about every minutes, is there a way to disable it?

Hi, The recent version of FS( I think I had notice that also on 1.0.1 stable version) seems sends out an INVITE msg every minute when I originate a call from a SIPUA(say X-Lite), then the SIPUA will respond 200 OK with SDP msg. There's no problem with X-Lite but some bad SIPUA can send bad responding msg and will cause FS hangup the call said "Malformed Session Description". I know it's not FS's problem, but I don't understand why it send the INVITE(a re-INVITE?) every minute? is there a way to disable it? btw, it only happens when you originate a call from a SIPUA, I originate from FS(originate sofia/defaut/1000 &echo) doesn't get re- INVITE msg.