Grey rectangle in the top left corner on iOS using Corodva plugin

When opening a PDF there is a small grey rectangle in the top left corner. It disappears when you tap to hide the navigation bar. Please have a look at the screenshots. Could you help and tell me where to fix that?

There is also a thin light line between statusbar and navbar, which should not be there ...

Thanks for your help!

I figured it out: the grey rectangle was part of the page number label, but the text had color [UIColor clearColor].
But I could not fix the strange line, can you help me with this issue?

We're investigating it and will publish the fix/solution as soon as possible.