Modded items event fails BlockBreakEvent to mcMMO (v1.5.08)

[OfficialGDog]

Hi, I'm trying to use MCMMO in my Aether Server.

The plugin works great until I try to destroy a modded block despite me having configured it in the modded blocks yml file.

I'm disappointed as I paid £8.00 to support the developer and I've just experienced this annoying bug.
Do you have any idea what I'm doing wrong?

I downloaded 1.5.08 because my server is running on 1.12.2 and this version is listed STABLE for that version. Please could you help me I will try updating MCMMO to see if that helps.

Please look at my configuration below:

./config.yml
Tool_Mods_Enabled: true
Armor_Mods_Enabled: true
Block_Mods_Enabled: true
Entity_Mods_Enabled: true

#######
./mods/blocks.default.yml
Mining:
# Aether Grass
X4096|0:
XP_Gain: 99
Double_Drops_Enabled: true
Is_Ore: false
# Aether Dirt
X4098|0:
XP_Gain: 99
Double_Drops_Enabled: true
Is_Ore: false

Thrown Exception:
[Server thread/ERROR]: Could not pass event BlockBreakEvent to mcMMO v1.5.08
org.bukkit.event.EventException: null