We've a problem with the caller id in one transfer scenario:

In our Example Party A calls Party B, Party B answers the call and transfers it to Party C. We're talking about the Caller ID in the phone of Party C now.

If B is doing an attended or unattended transfer, the caller id ist updating correctly as you would expect it.

But there's a third scenario, which is very common for users of older PBX systems: A so called "semi-attended transfer".

This means, that Party B is initiating A attended transfer via BLF Key, but hangs up, before Party C has answered the call.

In this case, the Caller ID should update to Party A, as soon as B hangs up his phone.

But this is not happening: The Caller ID remains on Party B until C answers the call.  Only then the caller id is updated.

Why is the caller id not updated after B hangs up and before C answers the call?

Is there any possibility to change this behaiviour?