[Bugfix][VoxCPM2] Fix VoxCPM2 concurrent speech quality (#4319)

Signed-off-by: CHEN <116010019@link.cuhk.edu.cn>
Co-authored-by: Sy03 <1370724210@qq.com>

vllm_omni/model_executor/models/voxcpm2/voxcpm2_talker.py

@@ -824,7 +824,7 @@ def _optimized_solve_euler_with_noise(
             t = t - dt
             if step < len(t_span) - 1:
                 dt = t - t_span[step + 1]
-    return x
+    return x.clone()
 
 
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