It is true that those overpriced airbridges cause ill engine functioning but so also does that smooth couplier.
They also give zero gains since the cylinder volume is small and increasing flow outside the engine does not make cylinder volume any larger.
GM is not stupid and their coupler is designed to work correctly with the PCM's adaptive strategy and to reduce air movement sound.
I make a cold airbox called the Icebox, it was deisgned to tottaly enclose the Blackwing and only allow the colder airflow coming from a hole behind it via shroud.
In your case what happens is when your driving the engine gets better colder airflow and adjusts the AFR but then when butterfly of throttlebody closes the pressure changes and now engine gets the hotter engine bay air which causes the PCM to adjust again thus this causes PCM to ramp back and forth from a richer to leaner state
So you either have to block off that hole and live with the hotter airmass which does not make as much HP or install a box like the Icebox and only allow the colder outside air into filter.
ANY leak, even the slighest from aircleaner to TB will cause weird effects for its unmetered and the adaptive strategy was never designed for that condition.
Consider my 1999 C5 is about 500 HP at flywheel and I still use stock MAF, airbridge, coupler and TB and none of those are causing a limit of airflow even when I went 217 MPH.
My Blackwing is now 5 years old and still functions as well as day it was put in with cleaning it about once a year and BTW the new C6 Z06, GM is using now a Donaldson filter.