Just removed the KB4515384 Windows 10 update and the issue was instantly solved

After playing in multiplayer world for a while, the audio began sounding wrong, as if sounds where being played beside/behind me.

Looking up will also heavily lower walking sounds.

This bug happened in the "late" game, after defeating the dragon and obtaining the elytra wings, and is permanent and in all new worlds created as well as old ones.

What I tried :

• Teleporting to the nether
• Dying
• Loading up another world
• Restarting Minecraft
• Restarting my PC
• Reinstalling Minecraft

None of these attempts removed the bug.

I had to trim the attached video up to a point where it is almost unusable, the full one is available here and here

There is no delay between video/audio in this video