Fix cfg being calculated more than once if sampler_cfg_function.

comfy/samplers.py

@@ -250,10 +250,11 @@ def sampling_function(model, x, timestep, uncond, cond, cond_scale, model_option
             uncond_ = uncond
 
         cond_pred, uncond_pred = calc_cond_uncond_batch(model, cond, uncond_, x, timestep, model_options)
-        cfg_result = uncond_pred + (cond_pred - uncond_pred) * cond_scale
         if "sampler_cfg_function" in model_options:
             args = {"cond": x - cond_pred, "uncond": x - uncond_pred, "cond_scale": cond_scale, "timestep": timestep, "input": x, "sigma": timestep}
             cfg_result = x - model_options["sampler_cfg_function"](args)
+        else:
+            cfg_result = uncond_pred + (cond_pred - uncond_pred) * cond_scale
 
         for fn in model_options.get("sampler_post_cfg_function", []):
             args = {"denoised": cfg_result, "cond": cond, "uncond": uncond, "model": model, "uncond_denoised": uncond_pred, "cond_denoised": cond_pred,