Phone termination issues

[nikko]

Hello,
I am not sure if support answers forums faster than emails so i will try both. I am considering upgrading some older polycom phones in the call center to Yealink phones on the advise of a vendor. I ordered one T38 to test but after recieving and setting it up in a PIAF environment, the phone has some termination issues. Here is what it does.
when i make an outbound call, the terminating phone will ring quickly and hang up and show a missed call, then it will ring again, all the while the originating t38 shows as ringing with one call. I have not seen anything in the logs to indicate this is two calls and cannot understand what causes this behaviour. this is a default set up with only the acct name and pw added. all other default settings were left alone. this behaviour is non existent in all the polycom phones that have a basic default setup as well. I have sent a pcap via email to support if that helps.

thanks