My custom config keeps getting overwritten to the default file every time I open the game, thus making it impossible for me to add weapons from other mods.

Setting the file to 'read only' crashes the game.

This is what happens i the log

Fixed, had to add "custom_weaponry." before every weapon.
Es:
[mekanism_disassembler] // should be // [custom_weaponry.mekanism_disassembler]
registry_name = "mekanism:atomic_disassembler"
#Allowed Values: AXE, FIST, HOE, PICKAXE, SHOVEL, SWORD, SPEAR, GREATSWORD, KATANA, TACHI, LONGSWORD, DAGGER, BOW, CROSSBOW, TRIDENT
weapon_type = "GREATSWORD"
impact = 8.9
armor_ignorance = 0.4
hit_at_once = 3

I tried seeing the mod in 1.17 and the entire configs gets wiped clean every time, well, you should open a new issue about that.

I'm having the same issue, and prefixing it with "custom_entity" doesn't work:

[custom_entity]

    [custom_entity.dungeonsmod_guard]
        type_name = "dungeonsmod:guard"
        impact = 0.5
        max_strikes = 1
        armor_negation = 0.0
        #Allowed Values: ZOMBIE, SKELETON, CREEPER, SPIDER, VINDICATOR
        ai_type = "VINDICATOR"
        texture_location = "dungeonsmod:assets/dungeonsmod/textures/entity/guard.png"

it just wipes the config file and the log says
...epicfight.toml is not correct. Correcting
...Incorrect key custom_entity was corrected from SimpleCommentedConfig:{dungeonsmod_guard=SimpleCommentedConfig:{type_name=dungeonsmod:guard, impact=0.5, max_strikes=1, armor_negation=0.0, ai_type=VINDICATOR, texture_location=dungeonsmod:assets/dungeonsmod/textures/entity/guard.png}} to its default, null.

I'm using version 17.0.3 on Forge 1.17.1-37.0.82

@Yesssssman