Transfer Preset cancelled calls after 7 seconds

[vccsdotca]

Helloo!

I am unable to determine the cause of some behaviour using the preset transfer. The customer is using a preset to dial an external number which has a closer at the other end. According to my packet caps there are dozens of calls to that number where vicidial cancelled them after exactly 7 seconds, while the completed calls seem to happen if the switch sends a ringing or audio down the channel before 7-8 seconds. Other calls cancelled are adhering to the dial timeout which is 32 seconds. I was suspecting AMD but the cancels come before ringing as mentioned above. So just to recap;

-Dial Timeout = 32 secs (works with all numbers except transfer number)
-Dropped calls seconds = 24 secs
-Calls to transfer preset are being cancelled after 7 seconds of no ringing or audio packet sent back from the switch.
-Calls to transfer preset that are completed had a ringing or audio packet before 7 seconds.
-Transfer prefix is 88
-VICIBOX Server 1686 4.0.3

Thank you in advance.