[Bug]: MiniMax-M2.5 reasoning missing in chat completions stream

[JakubCerven]

Your current environment

The output of python collect_env.py

Your output of `python collect_env.py` here

🐛 Describe the bug

when serving vllm using vllm/vllm-openai:v0.17.0 + lukealonso/MiniMax-M2.5-NVFP4 --reasoning-parser minimax_m2

reasoning is not present when calling /v1/chat/completions + stream=True
it is working correctly with non-stream + /v1/responses

bellow is script that reproduces the issue

from openai import OpenAI

client = OpenAI(api_key=api_key, base_url=base_url)

print("=== Non-Streaming ===")
response = client.chat.completions.create(
    model=model,
    messages=[{"role": "user", "content": "hello"}],
)

message = response.choices[0].message
print(f"Reasoning: {getattr(message, 'reasoning_content', None)}")
print(f"Content: {message.content}")

print("\n=== Streaming ===")
stream = client.chat.completions.create(
    model=model,
    messages=[{"role": "user", "content": "hello"}],
    stream=True,
)

for chunk in stream:
    delta = chunk.choices[0].delta
    reasoning = getattr(delta, "reasoning_content", None)
    content = getattr(delta, "content", None)
    if reasoning:
        print(f"Reasoning: {reasoning}")
    if content:
        print(f"Content: {content}")

when running with same config on vllm/vllm-openai:v0.15.1 reasoning is streamed properly

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