microphone issue after screen replacement xt1254
i am a phone repair store and have been doing repairs for the last 5 years. i have even fixed the screen on this model phone many times in the past with no issues. however this time after putting the new screen people cant hear when talking on the phone. only on speaker phone. the weird part is while in a call not on speaker phone if i blow into the mic i can hear that sound on the other line, however no audio from a voice. i even tried taking the board out and talking directly into the mic just to make sure the hole wasnt obstructed in anyway. all looks fine. i know this phone has like 5 microphones so troubleshooting isnt easy.
also when i go to google and press the mic to do a voice search it picks up my voice perfectly, and in a call it picks up when i blow on the mic but not me actually talking. and idea on what could be causing this? because im stumped.