Microphone not working for Video Messenger

My iphone SE recently started having a microphone issue when using video messengers. It works perfectly for normal audio calls, either directly or through an app, but the moment I switch to a video call the other person can no longer hear me. When I plug in headphones (without a built in mic), the audio works again. I have checked all the microphone, app, and privacy settings and they all are green. I have tried rebooting the phone and reinstalling apps to no avail.

Is there a second microphone that gets used during video calls that could be having a hardware issue? or am I just looking in the wrong place to fix a software issue?