I'm not sure what I am doing wrong, but my BC doesn't turn out right. It looks like it is separating. You can see the shortening sweating out of it and it is not crusting. This seems to happen every so often and I don't know what I am doing wrong.

Generally that means too much liquid.
How long did you beat it? KitchenAid or hand held mixer?
What recipe did you use?

I used a kitchen aid. I used the wilton recipe and a recipe her on CC. Wilton used crisco, water, 2lb sugar and the flavoring. the CC used crisco and butter then water, sugar and flavoring. So that can happen if I use too much water?

What exact recipe did you use? How much water did you add to the 2 lb p/s? How much shortening or shortening/butter in each recipe? Are both recipes doing it?

what's the fat/sugar ratio? more fat ... less crusting.

My recipe uses about 1-1/3 cups shortening to 2 lbs of p.sugar and it crusts great.

Really it makes a difference. Water does not mix w/shortening (or butter). If you use too much liquid (whatever it be juice, milk, water) it will make the problem you describe.
Yes, the *exact* recipe does matter. Are you using 0 trans fat Crisco? Many are having trouble w/that. Is it really Crisco brand? A store brand might not be all vegetable fat.
So, yes, the *exact* recipe does matter. The more info you can give us that is *exact* will help us help you.

I use 1 cup crisco brand all vegetable shortening. the one that comes in remeasured bars. Then I added 1 stick of butter, then 2 lbs of the sugar, 2 tbs of vanilla, 1/4 tsp of almond and i add water as needed. About 5-9 tbs.