So technically speaking, this is probably where it’s happening.
When your stimulant level goes very negative to the point where it causes you to pass out it applies the downed effect, it applies the blind effect and it forces you to fall asleep. What I noticed however is that it doesn’t actually do anything to keep you asleep and the thing that keeps to the downed effect and the blinding effect from stacking is a check for whether you’re asleep not whether you’re downed.
Off the top of my head what I’m guessing is happening is that if your fatigue level is very low when you pass out then you fall asleep but you almost immediately wake up at which point the low stimulant level causes you to get the pass out drunk effect again, possibly several times in a row. I’m guessing that the wake up code is nullifying the downed and asleep condition when this happens, but the blind effect is accumulating.