Routing Audio while Mirroring to Default Audio Device

Hi all,
I use a projector with my iPad Pro in my classes in university. Starting with iOS 12 I started to encounter a problem while projecting.
When VO speech comes from the projector speakers, I use the rotor to @Audio Device@ and change the output device from external to default audio device.
However, VoiceOver speech becomes very distorted and it sounds like Mickey Mouse speaking with incredible speed. Nothing worked for me, I unpaired, re-paired, reset etc. Nothing seems to work for me. I emailed Apple Accessibility and they asked for a recording for this, the recording won't be possible as the audio comes from a 3.5 Apple headset, so I don't think I can capture the audio and how distorted it is. Has anyone gone through this? Is there any workaround for this problem?
Thanks all.