bottom left side of creative inventory is different from the other

That's just the shading, if you look at the very bottom left pixel, it is the same color as the main part of the inventory (the color precisely between the dark and light), the pixel that you highlighted is present on the left side, using that color.

Compare bottom left with top right, and top left with bottom right. Those are the same.

This is not a bug.

I understand. This was supposed to be a cosmetic bug

Thank you!

You can close this bug