This has been the case for a long time, but haven't been able to see a proper report for it.

The ender dragon can in some cases, play an excessive amount of sounds after sitting on the end fountain or when getting respawned with end crystals. Sometimes the sound count goes up to about +40 sounds just by the ender dragon roaring in the middle, when most of the time it doesn't play more than 5-8 sounds.

After further testing, seems like this only happens when the ender dragon is tracking the player, because this doesn't happen when the dragon goes to the fountain while the player is in creative or spectator.

This sound spam can be annoying for some players, and can even cause auditive issues if the volume is high enough.

How to reproduce

1. Go to the end, summon the ender dragon.
2. Set your gamemode on survival, wait until the dragon goes to the fountain.
3. You can see (or well, hear) how it makes an unreasonable amount of roaring sounds, check also the F3 debug screen.