Hey there! Just went through some tests and got some funky results.

Observations:

• Running fogbox with the following configurations shows vanilla fog in the overworld (tested underground):
  • Fogbox 1.19 Stable w/ Sodium/Iris
  • Fogbox 1.18 Stable with or without Sodium/Iris

• Running fogbox with the following configuration shows vanilla fog in the end:

  • 1.18.2 w/ Sodium/iris (works fine without)
    
    

• I couldn't get fogbox to render the "fogbox end" at all at first, but did realise that BetterEndSky, which I wrongly assumed would aid in testing, was causing the whole place to be invisible in a whole bunch of configurations (could explain #3 indirectly):

Hope this info helps 👍 let me know if i'm missing any context