After trying a few things on this thread, here are the steps I found worked for me to consistently stop the moodlet from coming back:
- Make sure your sim does have the 'Fear of the dark' trait (should show up at the bottom of the traits list in the sim profile bottom right ). If they do not have the trait but you are still getting the moodlet, add the fear trait using the cheat console with the command traits.equip_trait trait_fear_dark . When you add it you should see a notification like when the sim gets the fear so you know it worked, or just check the trait list.
- Once they have the trait, make sure your sim doesn't have the fear moodlet active. Go inside and wait it out (lasts 4 sim hours) or hide under sheets a few times to get rid of it faster (annoyingly you can't do this if there are positive moodlets getting in the way so make sure to expand the moodlets to check that it is gone, moodlet solvers don't work for it either smh).
- Once the moodlet is gone, wait for daytime before going outside, go outside during day hours for a bit to see if the moodlet pops up, you should only need to wait like 30 seconds:
- If the moodlet does not appear while outside during the day, yay, you should be good. You should immediately remove the fear with command traits.remove_trait trait_fear_dark, the moodlet should not come back while outside at night.
- If the moodlet does appear, then remove it but you'll have to start over from step 1 until it doesn't. Basically just removing and re-equipping the fear until it works, but note I will usually save and reload the game between each try, I'm not sure if that part is actually necessary, but at least I can say I have used this on 3 different sims and it has worked either the first or second time. Hopefully that means it shouldn't take too many tries for it to work.
A couple of things that may be important:
-I'm on console (PS4), so obviously no mods and also only have the base game installed, no DLC yet.
-In case you need it, to activate the cheat command prompt on console you press all the shoulder buttons together (ie. L1+R1+L2+R2 on PS4), be careful while doing this to not accidentally select another sim, make sure the active sim is the one you need to use it on.
-Note that you do NOT have to have testingcheats on for the above trait commands to work, not sure if that factors in to the workaround being effective, but at least I have it off and the commands to remove and equip traits still work
-The glitch seems obviously related to something that will cause the moodlet to appear during the day regardless of having the trait or not, which is why i take the extra step to get rid of it, waiting for daytime to check, etc. Removing/Re-equipping the trait (i guess) will reset whatever it is glitches it out and so far it seems totally random whether it will happen or not.
