Audio isn't playing when I'm outside of attenuation range.

That has the exact same effect as the Play node. The sound only starts playing when you enter the attenuation radius.

It seems to virtualize the sound correctly after you enter the attenuation radius once (i.e., if you leave and come back, the music is all still synced up). I might try spawning each sound at the player’s location (with the volume at 0) and then moving them to their actual position in the level.