Vid author borrowed the original design from PurpleMentat, where it was built in AgS.  Vid author is playing CL, not a skyblock.  I'll work on lighting, as my current design does not stay at cap either.  Still does not explain how this works for her, but not me 
Pitch black inside when I closed it up.  All traps in open position.  ZA settings are whatever the packed shipped with.  I read somewhere about traps being susceptible to some kind of lighting bug [capturing daylight?].  I tried to avoid this by having the roof on before I placed any trap doors.
I honestly don't know what to make of it.  Her build works great.  My copy works like crap.