As
@AliOop said, this is ricing. For me, it has always been caused by a fragrance oil. I made soap yesterday with All Souls Day from Nurture Soap. I know it rices a little, but I love it enough to use it anyway. Unless the ricing is severe you can usually use your stick blender to smooth it out. When you know the fragrance will rice, add it when you reach, or nearly reach, emulsion. Then stir in the fragrance oil until you see the ricing, then use the stick blender to smooth it out. Unless I know that the fragrance doesn't also accelerate, I generally don't do anything overly fancy so I don't go beyond medium trace. If it happens the first time I use the FO and I am not expecting it, I usually have to pivot from my original plan and wing it. Simple hanger swirls are usually my 'save'.