Does anyone know why the color change affects the second button?

I'm learning how to use buttons in Swift and I'm changing the color of several of them separately when they are pressed. The problem is that when I press the second button the first one also changes color, and I find it somewhat strange since in theory they are two different functions and one should not affect the other. Anyone know what might be happening?

//
//  ViewController.swift
//  EjemploProyecto
//
//  Created by Mario Miranda  on 17/4/22.
//

import UIKit

class ViewController: UIViewController {


    //Outlets

    @IBOutlet weak var myButton: UIButton!
    @IBOutlet weak var button2: UIButton!


    override func viewDidLoad() {
        super.viewDidLoad()
    
        //Buttons
        myButton.backgroundColor = .green
        button2.backgroundColor = .blue
    }

    @IBAction func buttonAction(_ sender: Any) {
    
        if myButton.backgroundColor == .green
        {
            myButton.backgroundColor = .blue
        } else
        {
            myButton.backgroundColor = .green
        }
    
    }

    @IBAction func buttonAction2(_ sender: Any) {
    
        if button2.backgroundColor == .blue
        {
            button2.backgroundColor = .gray
        } else
        {
            button2.backgroundColor = .blue
        }
    
    } 
}