Hi there,
My name is Kamran and working at Truecaller as an Customer support manager.
It sounds like the Caller ID is enabled as you receive the "After call search notification", which is a part of the Caller ID feature. In order to receive the instant live caller ID, we require at least 3G or WiFi connection due to technical reasons which is beyond our control.
I would like to add that Truecaller is not specifically developed for "Developer Preview", therefore some small issues could appear.
If you have any questions or concerns, please don't hesitate to contact our "support at truecaller.com". We will try to reply as fast as we can.
Have a nice weekend!
Best regards,
Kamran