The cause of the delay may be due to the ‘Cut Through’ time being set to too long of a period under Configure/Channels/Terminate Subs/Answer/Cut Through.
Basically by setting the Cut Through Time to x, this is “the time that a terminate channel waits (after answering a call) before it sends a path confirmation signal to the originate channel”. Please set this accordingly for your testing needs; the default is .8 seconds.