The ghast fireball noise can be heard by players who are out of the sound radius if another player is in the radius of the normal ghast sounds.

Appears to only happen if the other players have had the ghast loaded recently on their computers, but unsure on that.

Reproduced in creative:
https://youtu.be/dTtNpPOZgVM
I put someone next to the ghast in survival and got them to aggro it, then I traveled further and further away. Got over 200 blocks before I decided to end the test.

This is extremely obnoxious since there's no way to turn down only mob sounds in Bedrock, and also because it may cause players in the nether to believe they're being shot at when it's another player.

Edited to add: also unlike most mob sounds, the ghast "scream" from shooting a fireball does not get quieter with distance. Am not sure if this may be the case with other mob projectiles such as blaze fireballs or it's a unique problem.