Mining takes longer when repeatedly jumping in‑place while mining the block you are standing on

Summary

Brief loss of the onGround state during in‑place jumps repeatedly triggers the airborne mining speed penalty, causing real‑time mining progress to slow down noticeably in Minecraft Bedrock Edition. This is not only a visual effect.

Steps to reproduce:

1. Create a Survival world without any behaviour packs or cheats enabled.

2. Place a solid block and stand directly on top of it.

3. Keep holding the break button to mine this exact block.

4. Continuously spam the jump button while mining.

5. Compare the total breaking time with a control test (mining the same block without jumping).

Observed result:

The block requires significantly more time to break. Measurements show a clear time difference; this happens because each jump briefly sets onGround = false, activating the airborne mining multiplier many times during mining.

Expected result:

When the player is physically standing on the target block, mining speed should remain stable, unaffected by short‑lived airborne states from small jumps.