Why does webkit-linear-gradient work differently than linear-gradient?

Question

css

This code does not work correctly, but if you remove linear-gradients or describe -webkit-linear-fradient after the usual one, does everything work correctly?

/* НЕ то что мне нужно*/
body{
background:#556;
            background-size: 80px 140px;
            background-position: 0 0, 0 0, 40px 70px, 40px 70px, 0 0, 40px 70px;
            background-image: -webkit-linear-gradient(60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            -webkit-linear-gradient(-60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            -webkit-linear-gradient(60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            -webkit-linear-gradient(-60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            -webkit-linear-gradient(30deg, #99a 25%, transparent 25.5%, transparent 75%, #99a 75%, #99a),
            -webkit-linear-gradient(30deg, #99a 25%, transparent 25.5%, transparent 75%, #99a 75%, #99a);
            background-image: linear-gradient(60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            linear-gradient(-60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            linear-gradient(60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            linear-gradient(-60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            linear-gradient(30deg, #99a 25%, transparent 25.5%, transparent 75%, #99a 75%, #99a),
            linear-gradient(30deg, #99a 25%, transparent 25.5%, transparent 75%, #99a 75%, #99a);}

/** ВСЕ ОК*/
body{background:#556;
            background-size: 80px 140px;
            background-position: 0 0, 0 0, 40px 70px, 40px 70px, 0 0, 40px 70px;
            background-image: -webkit-linear-gradient(60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            -webkit-linear-gradient(-60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            -webkit-linear-gradient(60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            -webkit-linear-gradient(-60deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
            -webkit-linear-gradient(30deg, #99a 25%, transparent 25.5%, transparent 75%, #99a 75%, #99a),
            -webkit-linear-gradient(30deg, #99a 25%, transparent 25.5%, transparent 75%, #99a 75%, #99a);}