Urates could be coming out because soaking can encourage them to empty their bowels. If it was urates though, I would think it would mostly come out all at once unless there is just some stuck on the prolapsed area. Blood is not so much a good thing, but if the prolapse has been rubbed raw or something than it may bleed some. If it is coming out from somewhere internally though I would definitely have a fecal done.
I once rescued a baby ball python and it prolapsed--turns out it was loaded with internal parasites. My vet fixed the prolapse, put in a few stitches and we treated it for the parasites and it never had any further problems.