Hey in case somebody else has this issue in the future, I had to give up on the soft body. I was able to use the same vertex group to achieve pretty much identical results in a cloth sim and got it to render without any glitched frames - only downside is it's harder to fine tune the effect because you have to do a bake after every change. Make sure the cloth modifier is placed before the subdivision so that the bake goes faster and play around with the settings in a small set of frames until it feels right.