The minecraft:entity.player.splash sound can play an echo

I think there's a bit of misconception here; allow me to elaborate.

When water bottles are used on dirt, the minecraft:entity.player.splash sound event is played only once. At first, it may appear as if this sound plays twice, but this is just the nature of this particular sound event as, at one point, it goes quiet, and then all of a sudden, some extra noise can be heard again. To prove that this sound event is only played once, simply execute the command provided below and listen closely. You'll notice that the exact same sound is created as if you were making mud using water bottles.

/playsound minecraft:entity.player.splash master @a

Sorry for my poor wording. I did notice both splashes come from the same audio file.

Can confirm in 1.19.

Can confirm in 1.19.1.

Can confirm in 1.19.2.