Thanks for the link. 
I had backed up the problematic profile. So I can test your edits.
Unfortunately that didn’t fix the problem either. 
Crash report;
The game crashed whilst initializing game
Error: java.lang.RuntimeException: java.lang.IllegalArgumentException: Equal objects must have equal hashcodes. During rehashing, Trove discovered that the following two objects claim to be equal (as in java.lang.Object.equals()) but their hashCodes (or those calculated by your TObjectHashingStrategy) are not equal.This violates the general contract of java.lang.Object.hashCode(). See bullet point two in that method's documentation. object #1 =class cofh.lib.util.ItemWrapper id= 1199108907 hashCode= 334102529 toString= cofh.lib.util.ItemWrapper@1199108907{m:1, i:factorization.charge.ItemAcidBottle@1975825171, v:5098}; object #2 =class cofh.lib.util.ItemWrapper id= 1709161336 hashCode= 334102529 toString= cofh.lib.util.ItemWrapper@1709161336{m:1, i:factorization.charge.ItemAcidBottle@1975825171, v:5098}
İmage;
My jvm args: -Xmx10240m -Xms256m -XX:PermSize=256m -Dminecraft.applet.TargetDirectory=“C:\Users\gsera\Documents\Curse\Minecraft\Instances\gregtech6 (1)” -Dfml.ignorePatchDiscrepancies=true -Dfml.ignoreInvalidMinecraftCertificates=true -Duser.language=en -Duser.country=US
Log files;
2020-08-20-6.log (156.6 KB)
gregtech.log (6.2 KB)