I can hear .wav files but in the preview but not in the rendered product

Hi everyone, 

I'm working with a file with 1 .wav file and several .mp3 files, when I'm doing the check in the preview with the audio on, I can hear it perfectly fine, but when I render it with Encoder, it will play the sound of the mp3 files, but not the one for the .wav 

I saw that there were some issues in a CC2015 version a while back but I'm using 2020 and I find it really strange that it's only the wave files not being rendered. 

Does anyone have a solution or an idea of what could be happening? 

Thanks!