Description of the issue:

I get periodic crashes that seem to have no clear cause, so I am not sure what is happening. I am also contacting the creators of the other core mods.

Crashlog:

https://pastebin.com/ibF6zL1D

Versions & Modlist

forge 14.23.5.2814
opencomputers 1.7.4.153
infinitylib 1.12.2-1.12.0
agricraft 2.12.0-1.12.0-a6
codechickenlib 3.2.2.353
ancientwarfare 1.12.2-2.7.0.574
ancientwarfare 2.7.0.574
redstoneflux 2.1.0.6
ancientwarfareautomation 2.7.0.574
appliedenergistics2 rv6-stable-6
baubles 1.5.2
astralsorcery 1.10.11
autoreglib 1.3-26
backpack 3.0.2
patchouli 1.0-18
llibrary 1.7.18
bewitchment @Version@
bibliocraft 2.4.5
jei 4.15.0.268
forestry 5.8.2.387
binniecore 2.5.1.188
binniedesign 2.5.1.188
genetics 2.5.1.188
botany 2.5.1.188
extrabees 2.5.1.188
extratrees 2.5.1.188
biomesoplenty 7.0.1.2425
guideapi 1.12-2.1.8-63
bloodmagic 1.12.2-2.4.0-102
thaumcraft 6.1.BETA26
botania r1.10-360
chisel MC1.12.2-0.2.1.35
chiselsandbits 14.31
cofhcore 4.6.2
cofhworld 1.3.0
compactmachines3 3.0.15
asielib 1.0.0
waila 1.8.26
opencomputers 1.7.4.153
mcmultipart 2.5.3
mekanism 1.12.2-9.6.6.358
computronics 1.6.5
mantle 1.12-1.3.3.42
endercore 1.12.2-0.5.45
thermalfoundation 2.6.2
thermalexpansion 5.5.3
enderio 5.0.40
enderiointegrationtic 5.0.40
tconstruct 1.12.2-2.12.0.115
conarm 1.2.3
cucumber 1.1.3
dimdoors 3.0.9+287
dynamictrees 1.12.2-0.9.4
dynamictreesbop 1.12.2-1.4.1e
harvestcraft 1.12.2zb
dynamictreesphc 1.12.2-1.4.2
dynamictreestc 1.12.2-1.4.1e
ebwizardry 4.1.4
embers 1.12
enderiobase 5.0.40
enderioconduits 5.0.40
enderioconduitsappliedenergistics 5.0.40
enderioconduitsopencomputers 5.0.40
enderioconduitsrefinedstorage 5.0.40
enderiointegrationforestry 5.0.40
enderiointegrationticlate 5.0.40
enderiomachines 5.0.40
enderiopowertools 5.0.40
zerocore 1.12.2-0.1.2.8
bigreactors 1.12.2-0.4.5.65
forgelin 1.8.2
forgemultipartcbe 2.6.1.81
microblockcbe 2.6.1.81
minecraftmultipartcbe 2.6.1.81
fossil 8.0.0
gardenofglass sqrt(-1)
hammercore 2.0.4.2
justenoughreactors 1.1.3.61
librarianlib 4.15
mekanismgenerators 1.12.2-9.6.6.358
mekanismtools 1.12.2-9.6.6.358
mrtjpcore 2.1.3.35
mysticalagriculture 1.7.3
nei 2.4.2
ocdevices snapshot_20190228
openglasses 2.0.6
opensecurity 1.0-22
projectred-core 4.9.1.92
psi r1.1-72
plustic 7.0.5.2
projectred-compat 1.0
projectred-integration 4.9.1.92
projectred-transmission 4.9.1.92
projectred-fabrication 4.9.1.92
projectred-illumination 4.9.1.92
projectred-expansion 4.9.1.92
projectred-relocation 4.9.1.92
projectred-transportation 4.9.1.92
satako 2.23
sereneseasons 1.2.15
thaumic_calculator 0.4
thaumadditions 12r
thaumcomp 0.4.4
thaumicenergistics 2.2.1
thaumicperiphery 0.3.0
thermalcultivation 0.3.2
thermaldynamics 2.5.4
thermalinnovation 0.3.2
thutcore 5.19.9
thutcore_compat 1.0
thuttech 6.1.5
totemic 1.12.2-0.11.5
treegrowingsimulator 0.0.4
wizardry 0.9.9
worldedit 6.1.10-SNAPSHOT
orelib 3.5.2.2
immersiveengineering 0.12-89
librarianliblate 4.15
ocsensors 1.0.4

Are you using any frames (or similar) from ProjectRed Relocation? If so, can you try temporarily removing P:R Relocation? From a quick search they seem to be the only ones manually modifying the relevant fields.

This can be considered either a vanilla bug or bad documentation of the standard library, see the linked EnderCore issue; in any case it's completely unrelated to IE. It will probably be fixed in Forge soon-ish.