I always learn a lot when someone poses a question because I go look for research.
Looks like creatinine often doesn’t rise much at the beginning of a change in kidney function. So you may have caught it early. Or possibly your muscle mass has remained high (increased lately?) that would keep creatinine high. I’m certainly no expert, and only looking through research as I also have had changes in scores lately.
For people with diabetes 2, a drop in eGFR of 7.6% looks significant. So much depends on where your health is now, including weight and diet changes.

Here’s the articles I was reading. You may already have this info, but I thought I’d send it along.

Medscape sometimes requires a log in to access, but this looks like it’s open to the public, about creatinine:
https://emedicine.medscape.com/article/2054342-overview#a1
False Estimates of Creatinine Levels
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3383162/
About the prognosis of renal disease based on annual eGFR rate drops (in diabetics)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5743850/
Sorry I couldn’t be more helpful!