I have no idea what is directly causing this issue. - pretty sure its one of the following 3 though

 

forge 13.20.0.2227

I've been using flatworld (https://minecraft.curseforge.com/projects/flatworld?gameCategorySlug=mc-mods&projectID=254472) to fast dig. It pops a bunch of blocks at once.

I have an auto sort on a backpack set (https://minecraft.curseforge.com/projects/backpacks?gameCategorySlug=mc-mods&projectID=223957) to pick up cobble and dirt.

 

sometimes when using the flat tool i get the following crash report.

 

first line of error (for searching):

java.lang.IllegalArgumentException: Cannot get property PropertyEnum{name=variant, clazz=class net.minecraft.block.BlockStone$EnumType, values=[stone, granite, smooth_granite, diorite, smooth_diorite, andesite, smooth_andesite]} as it does not exist in BlockStateContainer{block=minecraft:air, properties=[]}

 

crash-2017-02-11_12.12.10-client.txt

Flatworld seems to be broken and sending incorrect commands to the blocks it's removing. 

can you tell me where that is in the vrash report? im trying to learn to read these.

    at net.minecraft.block.Block.func_180653_a(Block.java:557)
    at net.minecraft.block.Block.func_176226_b(Block.java:550)
    at com.ch1a.flatworld.ItemFlattening.itemDrop(ItemFlattening.java:144)
    at com.ch1a.flatworld.ItemFlattening.checkDropItem(ItemFlattening.java:135)

Straight forward

Thanks, missed that line i guess