Minecraft: 1.12.2
Forge: 14.23.5.2854
Mods: 2

jei_1.12.2-4.16.1.302
Metallurgy-4-Reforged-1.3.0-beta.1

Report:
https://hastebin.com/hoxetovuxe.sql

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Got a crash while shoveling some Dirt Blocks with a Vulcanite Shovel.

EDIT
You can also get ghost blocks while mining with the Fissure Trait.

mmh I can't seem to reproduce this, and the crash report unfortunately seems to have expired.

the cause of ghost blocks is when a tool is so fast the server can't keep up and some blocks are removed on the client but not on the server, I've done some testing with a Efficiency IV, Fortune III Vulcanite shovel to make sure I have the highest occurrences of the effect in a small time window, although it looks like it keeps up with it fine (test was done in singleplayer)

this might be a side-effect of 5ca263f that I wrote when you shared those profiler results on discord.

anyways I'll soon release beta.2 so I can re-open this issue if it persists