Copy & Paste in Omni Graffle 5

Hi,

I am using Omni Graffle for quite some time now. Since a couple of days, I have a strange behaviour that I cannot reset. Whenever I copy and paste an object, the first paste is fine, the second paste becomes a pdf or image. So if I e.g. copy a text, the first paste is editable, the second is not. Additionally, all pastes from the second onwards are placed in the center of the canvas.

This really kills me. Any help is appreciated very much!

Cheers,
Keyan