Hello supersteff,
It always works, if there is a bug, it is the first time I hear there is such an issue.
You do know that the files are generated depending on the size of the image sizes set-up in WordPress and from the full-size, right? If the full-size is not big enough, of course the images cannot be generated. Which is why there is a dashboard, a details button, etc, it’s to be able to check all that.
Can you take a screenshot of your Retina dashboard?
ereignislichter.de/SCR.zip
So first, there is a color bug in my plugin. It is displayed as ORANGE (can be generated) but actually it should be RED (cannot be generated).
You can see some red though, under the image name, there is the resolution of your full-size. Your full-size is actually too small of… 1 pixel.
The large size retina needs to be 2048×1530 but your full size is 2048×1529. So that’s definitely the problem.
So now, the solution for this is to upload/replace with a new full-size slightly bigger. Can you do that? On my side, I need to correct those colors or allow 1-3 pixels margin for the creation of the retina (since it wouldn’t affect the display much). What do you think?