I've tried different things too.
Lights dim/bright/off.
One litter box vs 2
2 litter boxes with 2 different types of litter.
One train of thought leads me to puberty, but that's a whole nother issue that I'm tossing around.
Made an enclosure built with wood, hot glue and tears on the cheap for my free roamers. The front comes off via a threaded rod through eyelet connection and the rubber covered base is strong enough to stand on.
It's not a trivial amount either. I swear she (ginger) saves up all day just to do it at night. The boy (shadow)has perfect habits. (He has from day 1 )
My 4 month old Flemish has developed a bad habit of pooping (only at night) all throughout the enclosure.
The trick is that she only does it when I close up the enclosure at night.
If I leave them out then it's maybe one or 2 misses.
She's obviously trying to tell me something..
I'm just tired...