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Mine had a really long permolt fasting phase (+/- 6 months). A few weeks before the molt, she would wander between her hide and the corner she ended up molting in, she also became quite sluggish. Mine never had a proper bald spot (how I can tell when my B. Boehmei is ready to flip over) or got considerably fatter like my LP, GBB and A. Geniculata, but looked greyer/duller than normal (she's quite red and pink usually).
What is normal for a Rosea, lol? But yes, it might be making more space inside its hide to flip over. My B. Boehmei constantly fills up his water bowl with substrate. One theory is apparently, that species who like it dry (like G. Roseas) do it because they find their enclosure too damp.
Or it might just do it, because it can, lol (same with the expansion of its hide), who knows what goes on inside their brains?
I've waited well over a year for mine to molt, by the way (mine's a young female, still has a little bit to grow). Definitely a species that requires patience. But once they emerge with their new beautiful colours, it's definitely worth it.