1.2 popup picture gets blurry on my Android 4.0 phone, also on the demo page

1.2 popup picture gets blurry on my Android 4.0 phone, also on the demo page

I'm trying out the new 1.2 popup features and I've tried to make a nice popup picture with it on my site. It worked really nice at first but, when I added the dark semi transparent background (the 'screen' as they call it) the picture turns really blurry/low res. Actually when I open the popup the picture shows right away but the dark screen takes a moment to show up, along with the blurriness. I turned off all animations on my site but the dark screen still seems to fade in.

I tried if the popups on the demo page have the same problem and they do (pinch zoom on the popup to see that the pictures is really blurry):
http://jquerymobile.com/demos/1.2.0-alpha.1/docs/pages/popup/popup-images.html

This all occurs on my Android 4.0 phone on a webkit browser (stock and Dolphin).
On my other Android 2.3 phone there seems to be no problem though, neither with Opera Mobile.