You have uncovered a bug.
While the contents of the clipboard from a cut/copy from within SO2 is not available outside of SO2, the reverse is not true. You can copy/cut from outside of SO2 and paste into SO2. I observed these behaviors on several devices, with several operating systems, in Word documents, PowerPoint Presentations and Excel spreadsheets.
I'll issue a bug report on clipboard behavior, and we'll try to correct it for the next release. Unfortunately, I cannot give you a time estimate.
Thank you for reporting this issue.