[2020] 9.0.4 experience gain bug.

This is not a bug - the difficulty settings apply globally for all worlds currently. We want to eventually change that, but currently that's how its working. You can edit them via in Configs/Difficulty.eco in your server files. (Steam/steamapps/common/Eco/Eco_Data/Server)

{
"CollaborationPreset": "HighCollaboration", # Irrelevant in text config
"DifficultyModifiers": {
"SpecialtyCostMultiplier": 2.0, # The higher, the longer it takes for you to be able to take another specialty
"SkillGainMultiplier": 1.0, # The higher, the faster you gain skills
"SpecialtyExperiencePerLevel": 25.0, # The higher, the more xp you need for leveling up a specialty (Double is four times the xp)
"CraftResourceModifier": 1.0, # The higher, the more crafting recipes cost
"CraftTimeModifier": 1.0, # The higher, the longer crafting recipes take to complete
"PlayerExperiencePerSpecialtyExperience": 0.0 # For each time you gain experience for some skill, you also gain progress to your next specialty. Use extremely low values. (0.00001 e.g.). Not recommended to use by us at all and not officially supported.
},
"EndgameCraftCost": "Expensive" # Normal for default Computer Lab Recipe, Expensive for a much more difficult Computer Lab
}