Wow! This is an original alpha seed. Beta seeds are in an eight-character format now.
Anyway, I’ve finally found a moment to look into this. This is intentional. You’re facing the portal that you exited to get here. It’s about 85 meters above you from this location. It sounds a bit louder because structures have a brighter sound than the surrounding terrain. Ideally this helps teterhedra, portals, etc. stand out against varied terrain like this.
I’m wrapping up the new update to release within the next week. It will include some mixing adjustments to cues like these.