If the image is already in the cache, the status property remains set to Image.Null. This is probably due to the path where loadImageFromDevice() results in instant QQuickPixmap::Ready status in qquickpdfpageimage.cpp:101 and on. In that path the thisRequestFinished() and thisRequestProgress() slots are never connected or called and the statusChanged() signal is not emitted. This can be reproduced by placing two PdfPageImage-s with their documents set to the same source URL and page number. To further corroborate the cache indeed uses URLs as part of the keys:

QQuickPixmapKey key = { &url, &requestRegion, &requestSize, frame, providerOptions };

This is completely fine and very nice but the reaction to QQuickPixmap::Ready should be setting status to Image.Ready and emitting the statusChanged() signal. Thank you in advance for your help.