1.21+ clients mine slower with Mining Fatigue when using high Efficiency tools on <1.21 servers

[fongos535]

General Information

https://dump.viaversion.com/395540424a789e609eb1f506d74deb32aae79d95e491e18b8500962b948f3c3c

Bug Description

When connected to a server running Minecraft version below 1.21, clients on 1.21+ experience significantly slower mining if affected by Mining Fatigue and using high Efficiency tools (higher than V). In the video I'm with mining fatigue 2 comparing the speeds of breaking the block between 1.21.8 to 1.20.6

1.21.8 https://github.com/user-attachments/assets/5c4b83b1-f14e-4bfb-be0b-cd3af8587ce1

1.20.6 https://github.com/user-attachments/assets/906bc984-d0eb-469f-a39c-524d5192d5b4

Additionally if you have a really high efficiency it would break the block with delay.

Steps to Reproduce

1. Join a server below 1.21
2. Give yourself a tool with high efficiency and the mining fatigue effect (more noticable with lvl 2)
3. Break a hard block
4. Compare it to 1.20.6 and see it's slow

Expected Behavior

The block should break as fast as 1.20.6, not slower.

[FlorianMichael]

This was fixed in the newest updates. Thanks for reporting