High memory usage when updating QtQuick Image

This is the first bug report I am submitting, so please let me know how to improve on the quality.

I am using a custom image provider to display a stream of images. On every update I update the source of the image like this

liveImage.source = "image://" + imageProvider + "/grayscale" + Math.random()

in order to avoid caching.

This worked fine in 5.8, however since switching to Qt 5.9 memory usage constantly increases with every new image until I run out of memory.

The problem can be reproduced using the image provider from the Image Provider example and a timer to update the image:

Timer {

 interval: 20

 running: true

  onTriggered: {

    img.source = "image://colors/yellow" + Math.random()

    console.log("update") running = true

}

Image {

  anchors.fill: parent;

  id: img;

  source: "image://colors/yellow"

}