Fix fp16/bf16 for pipeline_wan_vace.py

Author: SlimRG

src/diffusers/pipelines/wan/pipeline_wan_vace.py

@@ -527,10 +527,16 @@ def prepare_video_latents(
         else:
             mask = mask.to(dtype=vae_dtype)
             mask = torch.where(mask > 0.5, 1.0, 0.0)
-            inactive = video * (1 - mask)
-            reactive = video * mask
+            
+            inactive: torch.Tensor = video * (1 - mask)
+            reactive: torch.Tensor = video * mask
+
+            inactive = inactive.to(dtype=vae_dtype)
+            reactive = reactive.to(dtype=vae_dtype)
+
             inactive = retrieve_latents(self.vae.encode(inactive), generator, sample_mode="argmax")
             reactive = retrieve_latents(self.vae.encode(reactive), generator, sample_mode="argmax")
+            
             inactive = ((inactive.float() - latents_mean) * latents_std).to(vae_dtype)
             reactive = ((reactive.float() - latents_mean) * latents_std).to(vae_dtype)
             latents = torch.cat([inactive, reactive], dim=1)