clumps stalling out the server

[Time6628]

I am currently running

• SpongeForge version: 1.12.2-2768-7.15-RC3522
• Forge version: 14.23.5.2797
• Java version: OpenJDK 1.8.0_181
• Operating System: Debian 8

• Plugins: Minecraft, Minecraft Coder Pack, SpongeAPI, Sponge, BetterChunkLoader, Buycraft, CatBot, CatClearLag, EconomyLite, GriefPrevention, HuskyCrates, HuskyUI, NytroUtils, LuckPerms, NuVotifier, Nucleus, Plan, Prism, SimpleAntiAFK, SkyClaims, TokenShop, Vote4Dis, Voteparty, spark
• Mods:

  Minecraft, Minecraft Coder Pack, Forge Mod Loader, Minecraft Forge, SpongeAPI, Sponge, /dank/null, AE2 Stuff, Actually Additions, Actually Baubles, AngelRing 2 Bauble, AppleSkin, Applied Energistics 2, ArchitectureCraft, Attribute Fix, AutoRegLib, Avaritia, B.A.S.E, BC Builders, BC Energy, BC Factory, BC Robotics, BC Silicon, BC Transport, BD Lib, Bad Wither No Cookie! Reloaded, Baubles, Bed Patch, Better Builder's Wands, Bonsai Trees, Bookshelf, Botania, Brandon's Core, BuildCraft, BuildCraft Lib, Building Gadgets, CXLibrary, Ceramics, Chameleon, Chance Cubes, Chest Transporter, Chickens, Chisel, Chisels & Bits, Clipboard, Clumps, CoFH Core, CoFH World, CodeChicken Lib, CommonCapabilities, Compact Machines 3, Cooking for Blockheads, CraftTweaker JEI Support, CraftTweaker2, Crafting Tweaks, Cucumber Library, Cyclic, Cyclops Core, Dark Utilities, Diet Hopper, Draconic Evolution, Ender IO, Ender IO Applied Energistics Conduits, Ender IO Base, Ender IO Conduits, Ender IO Integration with Forestry, Ender IO Integration with Tinkers' Construct, Ender IO Integration with Tinkers' Construct, Ender IO Machines, Ender IO Open Computers Conduits, Ender IO Powertools, Ender IO Refined Storage Conduits, Ender IO endergy, EnderCore, EnderStorage, Environmental Tech, Ex Compressum, Ex Nihilo Creatio, Exchangers, Expanded Equivalence, Extra Utilities 2, Extreme Reactors, FTB Quests, FTBLib, Farming for Blockheads, Fast Leaf Decay, FastFurnace, FastWorkbench, Faster Ladder Climbing, Flat Colored Blocks, Fluid Cows, Flux Networks, FoamFix, FoamFixCore, Forge Microblocks, Forge Multipart CBE, Gravestone Mod, Hammer Core, Hatchery, Immersive Engineering, Industrial Foregoing, Industrial Meat, Integrated Dynamics, Integrated Tunnels, IntegratedDynamics-Compat, IntegratedTunnels-Compat, Integration Foregoing, Iron Backpacks, Iron Chest, Just Enough Items, KleeSlabs, LLibrary, Let's Encrypt Craft, LootTweaker, MTLib, Mantle, McJtyLib, Mekanism, MekanismGenerators, MekanismTools, MightyEnderChicken, Minecraft Multipart Plugin, Missing Pieces, Mod Tweaker, ModPack Utilities, More Chickens, More Furnaces, Morph, Morph-o-Tool, Morpheus, Mystical Agradditions, Mystical Agriculture, No Mob Spawning on Trees, NoTemaStahp, Not Enough Wands, OpenBlocks, OpenModsLib, OpenModsLib Core, OreExcavation, Oreberries, PackCrashInfo, Pam's HarvestCraft, PetRock, Placebo, PlusTiC, ProjectE, Psi, QuantumFlux, RF Lux, RFTools, RFTools Control, RFToolsPower, Random Things, RandomPatches, RandomTweaks, Realistic Item Drops, Reborn Core, Redstone Arsenal, Redstone Flux, Roost, Sampling Performance Profiler, ShadowMC, Shadowfacts' Forgelin, Simply Jetpacks 2, Simply Light, Smooth Font Core, Snad, SonarCore, SpongeForge, Stone Chest, StoneBlock Dimensions, StoneBlockUtilities, Storage Drawers, Tesla Core Lib, Tesla Core Lib Registries, Thaumcrafft Inventory Scanning, Thaumcraft, Thaumic Terminal, The One Probe, Thermal Cultivation, Thermal Dynamics, Thermal Expansion, Thermal Foundation, Thermal Innovation, TickProfiler, Tinkers Tool Leveling, Tinkers' Construct, Tiny Progressions, Too Many Efficiency Losses, TorchMaster, Trample Stopper, Translocators, Twerk-Sim 2K16, UniDict, Universal Modifiers, Valkyrie Lib, Void Island Control, WanionLib, Wireless Crafting Terminal 2, WirelessRedstone-CBE, WorldEdit, XNet, Xtones, YABBA, YNot, Zero CORE, iChunUtil, mob_grinding_utils, p455w0rd's Library, uppers

Issue Description I've been getting this stall on various modpacks, according to someone in the sponge discord it's caused by an entity being spawned off the main thread: https://gist.github.com/Time6628/ba74cc84351d52c198657d5b403fd98d

[Time6628]

This is caused by the Clumps mod.

[Shybella]

I can also add stalls do happen with Clumps under SF. I was able to narrow it down with VisualVM.