How to reproduce:

1. Place a vine on the side of a block.
2. Break the block the vine is supported by (can use fire, leaf decay, player means)
3. Observe incorrect breaking sound.

Whenever I visited a swamp or jungle biome with naturally spawned vines, I heard this loud sound and thought it must be a player. It turned out to be naturally decaying vines due to world-gen incorrect vine placement.

In 1.12.2 vines make no noise unless directly broken by the player. On multiplayer servers, it could scare someone and make them feel that they are under attack / not alone.