How are you serving them? This is most often caused by an incorrect template. (the thing that tells the inference engine how to parse the think/tool parts of the answer)

For vllm the official recipe [1] (for another model in the same family) is this:

  --reasoning-parser qwen3 \
  --enable-auto-tool-choice \
  --tool-call-parser lfm2

[1] - https://recipes.vllm.ai/LiquidAI/LFM2.5-8B-A1B