Gemma-2 with Temperature=0 gives different output

Version: llama-cpp-python==0.2.82
Model: "bartowski/gemma-2-9b-it-GGUF/gemma-2-9b-it-Q8_0.gguf"

When I load the gemma2 model with temperature=0, and run a simple prompt, it always gives the same output.

However, when I enter long, complex prompts, the output changes.
Confusingly, if I repeat the same long prompt multiple times, the first and second results are different, but soon the output becomes same with iteration.

When I loaded the same model directly using the llama-cli in llama.cpp, I didn't have this problem.
Also, I didn't have this problem with llama-3. What could be the problem?

My test code is below

```
from llama_cpp import Llama

llm = Llama(model_path="~/.cache/huggingface//hub/models--bartowski--gemma-2-9b-it-GGUF/snapshots/d731033f3dc4018261fd39896e50984d398b4ac5/gemma-2-9b-it-Q8_0.gguf", chat_format="gemma", n_batch=512, n_ctx=8192, n_gpu_layers=-1)

output = llm("""You are a renowned historian specializing in ancient civilizations, and you have been invited to give a lecture on the political, social, and technological advancements of the Sumerian civilization, particularly during the Ur III period (circa 2100-2000 BCE). Your audience includes scholars, students, and history enthusiasts. Your lecture should cover the following key areas in detail:
1. Political Structure: Describe the centralized administration, the role of the king, and the bureaucratic system.
2. Economic Systems: Explain the agricultural innovations, trade networks, and economic policies.
3. Social Hierarchy: Discuss the class structure, roles of different social groups, and gender dynamics.
4. Technological and Scientific Contributions: Highlight key inventions, advances in mathematics and astronomy, and architectural achievements.
5. Cultural and Religious Practices: Explore their religious beliefs, major deities, and cultural contributions like literature and art.
Ensure your lecture is comprehensive, well-researched, and engaging, providing clear examples and drawing connections to how these advancements influenced later civilizations.""", # Prompt
max_tokens=8192, # Generate up to 32 tokens, set to None to generate up to the end of the context window
echo=False, # Echo the prompt back in the output
temperature=0.0
) # Generate a completion, can also call create_completion
print(output)

#When I run same Prompt and get output2, it is different from above output
```