https://bugs.winehq.org/show_bug.cgi?id=42674
--- Comment #2 from alexchandel@gmail.com --- This is still present in wine 2.8.
Notably, the crackling does not occur during the startup movie's audio (with the Bethesda logo). It only begins at the main menu's background music.
Moreover, this behavior can be triggered while Wine is already running, as long as the Skyrim process hasn't been started yet. That is, starting Steam with Wine set to Windows XP, then changing to Windows 7, then launching Skyrim is enough to cause audio crackling/distortions. Moreover, if one exits Skyrim (leaving Steam, and thus Wine, still running), sets Wine back to XP, then relaunches Skyrim, the audio crackling is gone.