I'm not sure how many forge versions are affected, but something on the forge side has broken, causing toml's to be read as a slew of "nulls" at a random point during Generating Keys.  Forge ON ITS OWN starts off the toml error by the following:

[23Jul2021 02:54:45.453] [Server thread/INFO] [net.minecraft.server.MinecraftServer/]: Generating keypair
[23Jul2021 02:54:45.509] [Server thread/WARN] [net.minecraftforge.common.ForgeConfigSpec/CORE]: Configuration file C:\Users\chris\AppData\Roaming\.minecraft\saves\New World\serverconfig\forge-server.toml is not correct. Correcting
[23Jul2021 02:54:45.510] [Server thread/WARN] [net.minecraftforge.common.ForgeConfigSpec/CORE]: Incorrect key server was corrected from null to its default, SimpleCommentedConfig:{}. 
[23Jul2021 02:54:45.510] [Server thread/WARN] [net.minecraftforge.common.ForgeConfigSpec/CORE]: Incorrect key server.removeErroringEntities was corrected from null to its default, false.

<<continues saying these keys were null, then it starts saying configs in the config folder were null as well>>

Then proceeds to do this to several other tomls afterward.  This usually results in the modloader forgetting the configurations set by users and loading the "defaults" into RAM instead, though it doesn't write them to the files.  It does this in both saves/world/serverconfig and .minecraft/config folders

 

Edited July 23, 20214 yr by KaleidioMakesGames

We determined this was due to the files not existing.
When a file does not exist, the values contained within also do not exist, and are therefore reported to us as null.