The bias toward the first presented candidate is interesting. The effect size for this bias is larger, and while it is generally consistent across models, there is an exception: Gemini 2.0.
If things in the beginning of the prompt are considered "better", does this affect chat like interface where LLM would "weight" first messages to be more important? For example, I have some experience with Aider, where LLM seems to prefer the first version of a file that it has seen.