I spent the last month figuring this out. I don’t know what causes it but if anyone ever comes across this try this… Set WOW to Windowed mode 1024×768. This seems to be the only mode that the cursor stays and the game remains in good 3d.
Now I know what is happening if in other higher res modes in WOW are used. After exactly 10 minutes, Vorpx is setting itself to Immersive Screen Mode then it is amplifying the cursors X/Y position. If you do change resolutions the cursor will come back but only shows the first X: 0-500 and Y:0-500 (top-left) of the underlying screen. It’s like Vorpx only shows the cursor when it’s in the top-left area of the underlying window.
I will submit a bug to Vorpx for this and see what happens.