Sim glass on clothes: triangle problem

Hi. I'm trying to make a lace dress so I used sim glass. It worked at the transparency part but those weird triangles emerging at folded parts. How can I fix this? here's the image's link. pleeeeeeez help me :(


drive.google.com/file/d/1c3LV5GWHtARErNj7NwsPJ--zsDXFAfT7/view?usp=sharing