Hello. I can’t say anyone has ever asked that before! I took a look, and I see exactly what you mean.
The entry note date is provided by GFCommon::format_date, which is not filterable on the Entry Detail page. There is an argument passed to the function for $is_human (which is what determines the relative date vs the actual date), so it could be filterable. If you think that would make a good addition to Gravity Forms, I recommend adding a note to our product roadmap. Click the blue plus in the lower left on this page to add a note for our product team: