[Bug] dsv32 encode_messages bug

[whybeyoung]

Checklist

• I searched related issues but found no solution.
• The bug persists in the latest version.
• Issues without environment info and a minimal reproducible demo are hard to resolve and may receive no feedback.
• If this is not a bug report but a general question, please start a discussion at https://github.com/sgl-project/sglang/discussions. Otherwise, it will be closed.
• Please use English. Otherwise, it will be closed.

Describe the bug

DeepSeek v32 has introduced the encode_messages feature, which results in discrepancies compared with non-3.2 branches when processing array-type messages.content, thereby causing model performance issues.

Reproduction

{
    "model": "xdeepseekv3testbo",
    "messages": [
        {
            "role": "system",
            "content": "You are a personal assistant running inside Clawdbot."
        },
        {
            "role": "user",
            "content": [
                {
                    "type": "text",
                    "text": "A new session was started via /new or /reset. Say hi briefly (1-2 sentences) and ask what the user wants to do next."
                }
            ]
        },
        {
            "role": "assistant",
            "content": [
                {
                    "type": "text",
                    "text": "Hey there! I'm Clawdbot, ready to help you out. What would you like to work on today?"
                }
            ]
        }
    ],
    "stream": false
}

Environment

h20