Somehow created an invisible vertical slab block when breaking two vertical cobblestone slabs in one blockspace. Its name showing up through the Jade mod had changed from what it originally was too. This glitched block was unbreakable in survival mode, so I switched to creative. Breaking this glitched vertical slab in creative immediately crashed my game. Log attached.

crash-2023-01-26_16.37.51-client.txt

other than the crash is breaking the slab in creative a viable fix to it?

Yep, although it crashed, it did get rid of the slab upon reopening the game. So thankfully it doesn’t damage the save.

any two vert cobble slabs produce this effect please fix

My crash report looks a little different from OP's, but they both seem to stem from the same null pointer
java.lang.NullPointerException: Cannot invoke "net.minecraft.world.level.block.state.BlockState.getSoundType(net.minecraft.world.level.LevelReader, net.minecraft.core.BlockPos, net.minecraft.world.entity.Entity)" because the return value of "cjminecraft.doubleslabs.api.IBlockInfo.getBlockState()" is null

The invisible ghost slab is still in place and I can't get rid of it. Any ideas how to do so?