Some information

Operating system: Win 10 x64
Java version: OpenJDK 8 Corretto 1.8.0_242
Minecraft version: 1.12.2
Baritone version: 1.2.12
Forge mods (if used):

I'm not sure if this even qualifies as a bug, but when doing #sel replace on large areas, aprox. 500x500x100 larger, can cause minecraft to completely freeze for several seconds. The effect seems to be intensified when the block to be replaced is rare or non-existent in the selected area, and when render distance is low.

Hm I rather think this is a gpu issue...
Mc has to render 250000 green squares...

Closing as won't fix, this isn't really a bug.