I found the opposite. GPT-5 is better at judging along a true gradient of scores, while Gemini loves to pick 100%, 20%, 10%, 5%, or 0%. Like you never get a 87% score.

I am running similar experiment but so far, changing the seed of openai seems to give similar results. Which if that confirms, is concerning to me on how sensitive it could be

Interesting, I'll give voting a shot, thanks.