Not Able to Write Last Cell in Pivot Table

[GalakFyyar]

I have the following code:

package main

import "github.com/tealeg/xlsx/v3"

func main() {
    f := xlsx.NewFile()
    sh, _ := f.AddSheet("Sheet1")

    // Write Colors (y-axis).
    colors := []string{"Red", "Green", "Blue"}
    for i, clr := range colors {
        cell, _ := sh.Cell(i+1, 0)
        cell.SetString(clr)
    }

    // Write Numbers (x-axis).
    numbers := []string{"1", "2", "3"}
    for i, num := range numbers {
        cell, _ := sh.Cell(0, i+1)
        cell.SetString(num)
    }

    f.Save("Bug.xlsx")
}

As you can see I'm trying to write three colors ("Red", "Green" and "Blue") as the Y axis.

However the resulting file looks like this, with the last color is missing.

Interestingly, I'm able to write the last color if I either write the X axis first, or don't write the X axis at all.

Go version: v1.18 Xlsx version: v3.3.7

Is this expected behaviour? Am I missing some sort of row allocating step?