diff --git a/vllm/patches/deepseek_v4_attention.py b/vllm/patches/deepseek_v4_attention.py
index db461b45..8286a288 100644
--- a/vllm/patches/deepseek_v4_attention.py
+++ b/vllm/patches/deepseek_v4_attention.py
@@ -583,9 +583,9 @@ def _apply_inv_rope_bf16(
     rope = o_f32[..., nope_dim:]
     y_even = rope[..., 0::2]
     y_odd = rope[..., 1::2]
-    # Inverse: sin → -sin
+    # Inverse: sin → -sin (swap signs on the cross terms)
     rope_out = torch.stack(
-        (y_even * cos - y_odd * sin, y_odd * cos + y_even * sin),
+        (y_even * cos + y_odd * sin, y_odd * cos - y_even * sin),
         dim=-1,
     ).flatten(-2)
     o_f32 = o_f32.clone()