diff --git a/modules/rng.py b/modules/rng.py
index 6eef8186..4a6e6f96 100644
--- a/modules/rng.py
+++ b/modules/rng.py
@@ -11,6 +11,7 @@ def randn(seed, shape, generator=None):
     if generator is not None:
         # If generator is not none, we must use another seed to
         # avoid global torch.rand to get same noise again.
+        # Note: removing this will make DDPM sampler broken.
         manual_seed((seed + 262144) % 65536)
     else:
         manual_seed(seed)