I added custom sound effects for a resource pack, one being a ring chime, another is a custom explosion sound effect, and the last being a song.

The ring chime plays every time I collect a gold nugget, and the explosion plays when I hold a Blaze Powder.

I placed two command blocks, one that will play the song, and another (Repeating Command Block) that will summon a gold nugget item in the coordinates I am in (~ ~ ~)

What I expected to happen was that the song would continue playing even though the ring chimes kept on playing due to the fact that I was repeatedly collecting gold nuggets, and the song to continue playing when I kept on switching between blaze powder and any other item in my hotbar.

What actually happened was:
The moment the ring chime played the 4th time in a row, the song stopped playing. The song also stopped playing the moment the explosion played the fourth time when I was quickly switching between it, and another item in the hotbar.

Steps to Reproduce:
1. Make a resource pack with custom sounds, one that is a song, and another being sound effects
2. Add it to your game of Minecraft
3. Use scoreboard objectives and other commands to make a sound play when you pickup a certain item of your choice
4. Use commands to make a sound play when holding a certain item of your choice.
5. Add two command blocks, one that will repeatedly give you an item that you chose for step 3, and another that will play the song
6. Use a button or a lever to make the song play
7. Either use a button or a lever to activate the command block that will repeatedly give you the items you chose for step 3, or keep on switching between the item you chose for step 4 and any other slot in your hotbar
8. You should be able to notice that the song suddenly stops playing.

I'll put a video I made since the video exceeds 10MB
https://www.youtube.com/watch?v=UEF5wgIA27c