twice on Google 3.1 Nano Banana (latest) the image was literally exactly the same as before. Maybe a millimeter zoomed in but I didn't ask for any zoom. So 20 credits and ZERO changes on edit mode.

One of the strengths of Google Gemini is the consistency between generations - its a feature users ask for when generating characters. If you used the same prompt and reference image, I would expect it to keep consistent. If you changed the prompt, clear your browser cache and try it again.