Mic recording not attached to screen recording

OK so this is extremely strange... I recorded a screen recording with a voice over using the mic on my iPhone.

It plays fine, with the voice over from the Photos app. But when I export it to an editing app (Lumafusion or CapCut) on the same phone, the file doesn't have the mic recording, just the original audio from the screen recording.

iPhone 13 Pro. OS up to date.

What gives man???