[MC-164254] Fish magically gain momentum and bounce up to 10 blocks in the air on slime blocks

If any fish is on a slime block, it will start bouncing, and slowly start accumulating momentum until it bounces ~10 blocks high every time.

Summon a square of slime blocks below your feet

/fill ~-3 ~-1 ~-3 ~3 ~-1 ~3 minecraft:slime_block

Obtain a cod, salmon, pufferfish, or tropical fish spawn egg
Spawn the entity of your choice on top of the slime blocks and watch it closely
Take note as to whether or not fish illogically gain momentum when bouncing on slime blocks
→ ❌ Fish illogically gain momentum when bouncing on slime blocks

Fish would not be able to illogically gain momentum when bouncing on slime blocks.

Here are some examples in videos:

[media]

Linked issues

Can confirm in 20w51a.

Can confirm in 21w14a.

Can confirm in 1.17.

Can confirm in 1.17.1.

Can confirm in 21w42a. Here are some extra details regarding this problem.

The Bug:

Fish illogically gain momentum when bouncing on slime blocks.

Steps to Reproduce:

/fill ~-3 ~-1 ~-3 ~3 ~-1 ~3 minecraft:slime_block

Obtain a cod, salmon, pufferfish, or tropical fish spawn egg.
Spawn the entity of your choice on top of the slime blocks and watch it closely.
Take note as to whether or not fish illogically gain momentum when bouncing on slime blocks.

Observed Behavior:

Fish illogically gain momentum when bouncing on slime blocks.

Expected Behavior:

Fish would not be able to illogically gain momentum when bouncing on slime blocks.

1 more comments

Can confirm in 1.18.2 and 22w12a.

Can confirm in 1.19.

Can confirm in 1.19.2.

Can confirm in 24w45a.

Can confirm in 25w34b