If you use your DK2 as the secondary screen, you have to set vorpX to “Show only on Rift DK2” display wise in the config app.
If that doesn’t solve the issue and you use mods, please try a fresh Skyrim install without any mods.
If that still doesn’t solve the issue, there might be something on your system interfering with vorpX. Generally everything that can interact with or show content over DirectX games can cause issues. Also temporarily disabling your antivirus program is worth a try.
Hot candidates are: graphics drver add-ons like Geforce Experience, or MSI Afterburner etc., desktop streaming apps like Splashtop, video recording software (FRAPS, OBS etc.) and many chat programs like (X-Fire, Skype etc.).