Yes, I use underwater tiles with different heights, the party can stand open-air knee-deep in water (height 0) when the adjacent tile is considered underwater (height -2), without unnatural boundaries in-between. So you can dive and emerge by simple walking, without jumps and ladders.You have both submerged and adjacent open-air tiles in your maps? (...with no barriers between?)
This didn't help. Apparently, the sound is blocked if it comes from an object below the water level at the moment when the party is not considered "diving". Eeven if you stand knee-deep in water next to the sound source.Is there a reason not to flag all of the map tiles as underwater?
I have no "fake" air tiles, just playing with different heihgts and slightly raised water surface.