Did you load Jessie and then Jessie FBM (or the hires variants), because if you did you get TWO Jessies in the scene one with morphs and one without. I didn't notice until after I posed one of the Jessies and found her evil twin standing there unmoved ... LOL The bikini fits just fine for me on unmorphed Jessie, but it doesn't contain any morphs, so if you morph her then taking the bikini through the cloth room is probably the only way to get it to fit the changed figure.
Mark