iPhone 12 pro max storage capacity

Hi!

Recently I noticed this problem/bug, I don’t even know how to call it: my iPhone 12 pro max storage capacity it’s wrongly displayed; it shows more available storage than the iPhone actual capacity. It’s an 128 gb but it shows 128-129 gb. How can be fixed this thing? I tried a full reset, looks the same. Besides this phone works like a charm, everything is smooth, just this bug is bugging me.

Thanks!