I reported this issue on July 22 on page 2 of the thread Removing the scrollbar from the post editor one of the worst "improvements" yet,
On page 4 of that thread, druesome claimed in an itemized "quick update on what's going on behind the scenes" that the issue was fixed, saying,
Copying and pasting issues in the Visual Editor were also resolved. Please test and drop us a report.
But, alas, the issues were not resolved as reported by druesome, and on page 6 of that thread I noted this in a response to his aforementioned list. However, I would like to modify my description of the issue in that thread. I had noticed only that text pasted from WordPad, Notepad, and YouTube (video codes) was being immediately stripped in the visual editor, and that's what I reported. Today I noticed that the problem is more general. Text pasted from anywhere (that I've tried so far) is immediately stripped when pasted into the visual editor.
In this thread, at Jul 26, 2014, 12:42 AM druesome again claims the issue has been resolved,
Glad to report that the pasting issue with the Visual Editor should be resolved now. Can you kindly test it out and give us a confirmation? Thank you!
Maybe it "should be resolved now," but it still isn't.