Why does the grid in Sketch set up incorrectly?

Question

Design

Hello. I create a 1320px wide grid with 12 columns.
The column width is 92, the gutter is 20.
For some reason, after every odd column, the gutter is 19px.
What is the problem?
Screencast of how I created the grid
jmp.sh/4wHOs9A

Answer 1

12 columns, so there are 11 middlemen between them. Calculate the column width:
(1320 - 11*20)/12 = 91.666.
There are no fractional pixels on the web, so either the column width should "walk", or the width of the middle. The sketch apparently chooses a walking centerpiece.
because of such jokes, I first manually carry out the calculations, and then I set up the grid in the programs.