Hi,
if it is transfered back to the network via 0800-number and then again routed to your aspect, these are 2 different incoming calls which have nothing in common like a call-id(from point of view of the ACD).
The first incoming call will have the field CFLAG1 = E
(means terminated by transfer). You should find the outbound-call to the 0800 number.
The only thing I can imagine is that the time when the calls are disconnected should be within the same second.
If the 2nd. agent who received the transfered call used wrapup, you'll have to substract the wrapup_time from term_time.