When iron golems hit a mob they knock it upwards. The distance of upward knockback is 8 blocks vertically, but for players a client-side correction was recently added (perhaps in 1.17.0?) that limits knockback to 3 blocks. The reduction from 8 blocks to 3 blocks is stated to be for Java parity per the resolution of MCPE-133996. However, the client-side-correction implementation makes knockback inconsistent between players and other mobs, it produces a glitchy animation in multiplayer, and it may contribute to other problems such as items dropping at unexpected places (MCPE-133181). Also, the 8 block upward knockback for non-player mobs itself contributes to issues such as ravagers being unable to hit iron golems (MCPE-101054).

Steps to reproduce

1. Set up an 8 x 8 solid block wall with a different color at each Y-layer, as a reference.
2. At one end of the wall, summon an iron golem and leash it to a fence.
3. Setup up a repeat command block with </execute @e[name = ***] ~~~ setblock ~ ~ ~ tripwire>. The *** should be replaced by a monster name (such as a husk) or by a player name as needed for testing.
4. Setup an impulse command block with a fill command to replace tripwire with a marker block such as diamond, then another command block with a fill command to replace the mark block with air.
5. Turn on the repeat command block and spawn a monster along the wall where the iron golem can hit it.
6. After the monster lands, turn off the repeat command block and use the marking command block to get a display of the mob's path through the air.
7. Clear the marking blocks using the other command block.
8. Change the name in the repeat command block to your player name and repeat steps (5) - (6) in both first and third person, observing yourself against the wall, noting your Y-coordinate changes, and with another person watching.

Expected results

Players and other mobs would receive the same vertical knockback from iron golems, it would match Java Edition (3 blocks), and it would look the same to all players.

Actual results

• Non-player mobs get 8 blocks vertical knockback Iron Golem vertical knockback.mp4
• Players get 8 blocks vertical knockback server-side Iron golem vertical knockback player.mp4
• Player Y-level shows 3 blocks vertical knockback Iron golem vertical knockback player slo-mo.mp4
• Player third-person view shows 3 blocks vertical knockback Iron golem vertical knockback third-person.mp4
• Players viewed by other players appear to get 8 blocks vertical knockback then teleport and float down to the 3-block level before falling Iron golem vertical knockback to other player.mp4