Sometimes when i place a Pipe or a Conduit this will happen:

---- Minecraft Crash Report ----

WARNING: coremods are present:
LoadingHook (Mekanism-1.10.2-9.1.1.290.jar)
FMLPlugin (InventoryTweaks-1.61-58.jar)
MalisisCorePlugin (malisiscore-1.9.4-4.1.1.jar)
Contact their authors BEFORE contacting forge

// Would you like a cupcake?

Time: 9/5/16 8:04 PM
Description: Tesselating block in world

java.util.ConcurrentModificationException
at com.google.common.collect.HashBiMap$Itr.checkForConcurrentModification(HashBiMap.java:339)
at com.google.common.collect.HashBiMap$Itr.hasNext(HashBiMap.java:345)
at mcmultipart.multipart.MultipartContainer.getExtendedStates(MultipartContainer.java:484)
at mcmultipart.block.BlockMultipartContainer.getExtendedState(BlockMultipartContainer.java:402)
at mcmultipart.block.BlockMultipartContainer.getExtendedState(BlockMultipartContainer.java:66)
at net.minecraft.client.renderer.BlockRendererDispatcher.func_175018_a(BlockRendererDispatcher.java:80)
at net.minecraft.client.renderer.chunk.RenderChunk.func_178581_b(RenderChunk.java:278)
at net.minecraft.client.renderer.chunk.ChunkRenderWorker.func_178474_a(ChunkRenderWorker.java:119)
at net.minecraft.client.renderer.chunk.ChunkRenderWorker.run(ChunkRenderWorker.java:47)
at java.lang.Thread.run(Thread.java:745)

A detailed walkthrough of the error, its code path and all known details is as follows:

-- Head --
Thread: Client thread
Stacktrace:
at com.google.common.collect.HashBiMap$Itr.checkForConcurrentModification(HashBiMap.java:339)
at com.google.common.collect.HashBiMap$Itr.hasNext(HashBiMap.java:345)
at mcmultipart.multipart.MultipartContainer.getExtendedStates(MultipartContainer.java:484)
at mcmultipart.block.BlockMultipartContainer.getExtendedState(BlockMultipartContainer.java:402)
at mcmultipart.block.BlockMultipartContainer.getExtendedState(BlockMultipartContainer.java:66)

-- Block being tesselated --
Details:
Block type: ID #348 (tile.null // mcmultipart.block.BlockMultipartContainer)
Block data value: 0 / 0x0 / 0b0000
Block location: World: (1660,238,-1033), Chunk: (at 12,14,7 in 103,-65; contains blocks 1648,0,-1040 to 1663,255,-1025), Region: (3,-3; contains chunks 96,-96 to 127,-65, blocks 1536,0,-1536 to 2047,255,-1025)
Stacktrace:
at net.minecraft.client.renderer.BlockRendererDispatcher.func_175018_a(BlockRendererDispatcher.java:80)

-- Affected level --
Details:
Level name: MpServer
All players: 1 total; [EntityPlayerSP['ZeetherTX'/983933, l='MpServer', x=1660.35, y=237.00, z=-1034.04]]
Chunk stats: MultiplayerChunkCache: 121, 121
Level seed: 0
Level generator: ID 01 - flat, ver 0. Features enabled: false
Level generator options:
Level spawn location: World: (1670,4,-1035), Chunk: (at 6,0,5 in 104,-65; contains blocks 1664,0,-1040 to 1679,255,-1025), Region: (3,-3; contains chunks 96,-96 to 127,-65, blocks 1536,0,-1536 to 2047,255,-1025)
Level time: 12059 game time, 12059 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: false
Forced entities: 2 total; [EntityPlayerSP['ZeetherTX'/983933, l='MpServer', x=1660.35, y=237.00, z=-1034.04], EntityMinecartChest['Minecart with Chest'/983837, l='MpServer', x=1601.50, y=123.06, z=-1002.50]]
Retry entities: 0 total; []
Server brand: fml,forge
Server type: Integrated singleplayer server
Stacktrace:
at net.minecraft.client.multiplayer.WorldClient.func_72914_a(WorldClient.java:498)
at net.minecraft.client.Minecraft.func_71396_d(Minecraft.java:2660)
at net.minecraft.client.renderer.chunk.ChunkRenderWorker.run(ChunkRenderWorker.java:57)
at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
Minecraft Version: 1.10.2
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 1853971864 bytes (1768 MB) / 3200253952 bytes (3052 MB) up to 5726797824 bytes (5461 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx6G
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
FML: MCP 9.32 Powered by Forge 12.18.1.2076 Optifine OptiFine_1.10.2_HD_U_C3 27 mods loaded, 27 mods active
States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored
UCHIJAAAAAAAAAAAAAA mcp{9.19} Minecraft Coder Pack
UCHIJAAAAAAAAAAAAAA FML{8.0.99.99} Forge Mod Loader
UCHIJAAAAAAAAAAAAAA Forge{12.18.1.2076} Minecraft Forge
UCHIJAAAAAAAAAAAAAA BiomesOPlenty{5.0.0.2080} Biomes O' Plenty
UCHIJAAAAAAAAAAAAAA Chameleon{1.10-2.1.7} Chameleon
UCHIJAAAAAAAAAAAAAA mcmultipart{1.2.0_74} MCMultiPart
UCHIJAAAAAAAAAAAAAA chiselsandbits{12.1} Chisels & Bits
UCHIJAAAAAAAAAAAAAA inventorytweaks{1.61-58-a1fd884} Inventory Tweaks
UCHIJAAAAAAAAAAAAAA JEI{3.9.0.246} Just Enough Items
UCHIJAAAAAAAAAAAAAA journeymap{1.10.2-5.2.4} JourneyMap
UCHIJAAAAAAAAAAAAAA malisiscore{1.9.4-4.1.1} MalisisCore
UCHIJAAAAAAAAAAAAAA malisisdoors{1.9.4-5.0.4} MalisisDoors
UCHIJAAAAAAAAAAAAAA mantle{1.10.2-0.10.4.jenkins163} Mantle
UCHIJAAAAAAAAAAAAAA Mekanism{9.1.1} Mekanism
UCHIJAAAAAAAAAAAAAA MekanismGenerators{9.1.1} MekanismGenerators
UCHIJAAAAAAAAAAAAAA MekanismTools{9.1.1} MekanismTools
UCHIJAAAAAAAAAAAAAA reborncore{2.6.2.27} RebornCore
UCHIJAAAAAAAAAAAAAA reborncore-mcmultipart{2.6.2.27} reborncore-MCMultiPart
UCHIJAAAAAAAAAAAAAA rftools{5.21} RFTools
UCHIJAAAAAAAAAAAAAA StorageDrawers{1.10.2-3.2.6} Storage Drawers
UCHIJAAAAAAAAAAAAAA tconstruct{1.10.2-2.4.0.jenkins325} Tinkers' Construct
UCHIJAAAAAAAAAAAAAA techreborn{1.4.0.45} TechReborn
UCHIJAAAAAAAAAAAAAA tesla{1.2.1.49} TESLA
UCHIJAAAAAAAAAAAAAA VeinMiner{0.34.1_1.9-73be663} Vein Miner
UCHIJAAAAAAAAAAAAAA VeinMinerModSupport{0.34.1_1.9-73be663} Mod Support
UCHIJAAAAAAAAAAAAAA icse{1.1.0.0} I Can See Everything
UCHIJAAAAAAAAAAAAAA wawla{2.3.0.202} What Are We Looking At
Loaded coremods (and transformers):
LoadingHook (Mekanism-1.10.2-9.1.1.290.jar)

FMLPlugin (InventoryTweaks-1.61-58.jar)
invtweaks.forge.asm.ContainerTransformer
MalisisCorePlugin (malisiscore-1.9.4-4.1.1.jar)
net.malisis.core.util.chunkcollision.ChunkCollisionTransformer
net.malisis.core.util.chunkblock.ChunkBlockTransformer
net.malisis.core.renderer.transformer.MalisisRendererTransformer
net.malisis.core.renderer.icon.asm.TextureMapTransformer
net.malisis.core.util.clientnotif.ClientNotifTransformer
GL info: ERROR RuntimeException: No OpenGL context found in the current thread.
Pulsar/tconstruct loaded Pulses:
- TinkerCommons (Enabled/Forced)
- TinkerWorld (Enabled/Not Forced)
- TinkerTools (Enabled/Not Forced)
- TinkerSmeltery (Enabled/Not Forced)
- TinkerGadgets (Enabled/Not Forced)
- TinkerOredict (Enabled/Forced)
- TinkerIntegration (Enabled/Forced)
- TinkerFluids (Enabled/Forced)
- TinkerMaterials (Enabled/Forced)
- chiselsandbitsIntegration (Enabled/Not Forced)

Launched Version: 1.10.2-forge1.10.2-12.18.1.2076
LWJGL: 2.9.4
OpenGL: ~~ERROR~~ RuntimeException: No OpenGL context found in the current thread.
GL Caps: Using GL 1.3 multitexturing.

Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: Yes
Is Modded: Definitely; Client brand changed to 'fml,forge'
Type: Client (map_client.txt)
Resource Packs: 
Current Language: English (US)
Profiler Position: N/A (disabled)
CPU: 4x Intel(R) Core(TM)2 Quad CPU Q6700 @ 2.66GHz
OptiFine Version: OptiFine_1.10.2_HD_U_C3
Render Distance Chunks: 5
Mipmaps: 4
Anisotropic Filtering: 1
Antialiasing: 0
Multitexture: false
Shaders: null
OpenGlVersion: 4.5.0 NVIDIA 372.70
OpenGlRenderer: GeForce GTX 750 Ti/PCIe/SSE2
OpenGlVendor: NVIDIA Corporation
CpuCount: 4

Hopefully this will be fixed in a later update ;)

ZeetherTX

Report to McMultipart.