Sounds Stop Abruptly

/playsound stops sounds halfway through. I happens whether they're resource pack sounds or Minecraft default sounds.

What I expected to happen was...:
Sound plays completely when /playsound was used.

What actually happened was...:
Sound stopped abruptly halfway through the sound.

Steps to Reproduce:
I used the mob.enderdragon.end sound, as well as some custom sounds in a resource pack. "/playsound mob.enderdragon.end @p"

It may be due to my world having a lot going on, but either way, there should'nt be a sound problem like this no matter what's going on in a world.