This is making me insane, I tried all kinds of CODECS, inserting diferent audio formats (mp3, m4a, wav), all of them the same result, bad audio on export and good audio on preview. Disabled hardware accelaration, cleared cache.
The audio (except the audio from other mp4 file in the project) is cracked and different pitch from original. I didn't make complexes audio edits, I only put them there.