when copying into scrivener (windows) from a pdf often the pasted text has short lines with unwanted carriage returns (line breaks)… no real workable solutions found … but then I stumbled onto Pantherbar, a copy/paste utility that is configurable with various extensions. Two I use are one that copies text with carriage returns extracted and pastes nicely into scrivener without any imported carriage returns. The second is where carriage returns are removed from any selected text that has been previously pasted.