Ive got a fluid sim in v2.82.7 and is rendered with Cycles. I am trying to use the 'use speed vectors' in the fluid sim while using the vector blur node but it blurs nothing. I do have the vector pass on; I tried turning odd de-noising in case that was it but to no avail. Its probably something little I'm missing but I cannot find it. The node setup and render are below. I am not sure what other info would be helpful to give.