ShaderEffect renders text wrong

import QtQuick 2.15
import QtGraphicalEffects 1.15
Item {
    id: root
    layer.enabled: true
    layer.samplerName: 'source'
    layer.effect: ShaderEffect {
        fragmentShader: "
            #version 330 core // My whole application is using core 3.3 so that matches the global profile. Changing it back to default profile does not fix the issue anyways
            uniform highp sampler2D source;
            uniform lowp float qt_Opacity;
            in highp vec2 qt_TexCoord0;
            out highp vec4 out_color;
            void main() { // Just pass the source texture through and apply opacity (does not change anything if I do not multiply by the opacity)
                out_color = texture(source, qt_TexCoord0) * qt_Opacity;
            }
        "
    }
}

MyItem {
    width: 350
    height: 200
    Rectangle {
        width: 50
        height: 50
        x: 3
        y: 3
        gradient: Gradient {
            GradientStop { position: 0.0; color: "red" }
            GradientStop { position: 1.0; color: Qt.hsla(1.0, 0, 0, 0) }
        }
    }

    Text {
        text: 'This is a test text. See if the text looks "normal"'
        color: 'red'
    }
}