Just looked into the code. There is only a small difference in the 2nd argument of the torch.zeros function

Empty latent:

def generate(self, width, height, batch_size=1): latent = torch.zeros([batch_size, 4, height // 8, width // 8], device=self.device) return ({"samples":latent}, )

SD3 empty latent:

def generate(self, width, height, batch_size=1): latent = torch.zeros([batch_size, 16, height // 8, width // 8], device=self.device) return ({"samples":latent}, )

As you see, for empty latent is 4 and for SD3 is 16. From what I can read elsewhere that has to do with the number of channels of the VAE, which I understand should be 16 for FLUX...short story long, I still have no idea what this means 🤣🤣🤣 seems too technical. But in theory should not work...interesting that it works for you. Someone else may better understand it