Some information

Operating system: Fedora 31 (Workstation Edition) (Kernel: 5.6.7-200.fc31.x86_64)
Java version: OpenJDK 64-Bit Server VM (build 25.242-b08, mixed mode)
Minecraft version: 1.15.2
Baritone version: 1.5.3
Forge mods (if used):
I'm using impact.

Exception, error or logs

2020-05-01-3.log

How to reproduce

Add your steps to reproduce the issue/bug experienced here.
I marked an area and then used
#sel set smooth_stone

Modified settings

To get the modified settings run #modified in game

Final checklist

• I know how to properly use check boxes
• I have included the version of Minecraft I'm running, baritone's version and forge mods (if used).
• I have included logs, exceptions and / or steps to reproduce the issue.
• I have not used any OwO's or UwU's in this issue.

I spotted similar crash, looks like approxPlaceable adds NULL to the array which then later crashes at:

public boolean matches(@Nonnull BlockState blockstate) {
        Block block = blockstate.getBlock(); // crash cuz blockstate is NULL
        return block == this.block && stateHashes.contains(blockstate.hashCode());
    }

that might be also issue from my side while porting baritone to Fabric :)

EDIT:
Crash log looks exactly the same as from my port so is an issue with Baritone.

EDIT2: BlockState is null for the items

[21:23:11] [main/INFO]: [STDOUT]: 2 kelp Block{minecraft:kelp}
[21:23:11] [main/INFO]: [STDOUT]: 1 tripwire_hook Block{minecraft:tripwire_hook}

also spotted that the inventory gets shuffled.

I was also having this problem, but I'm using Fabric. I reported it here, but idk if it's the same cause.