Is this just on Ravenloft or is it on any server? I have a similar issue with EE where somewhere some centimeters below my character icon & shortcut commands in the top right there's roughly a square block of space where my cursor will do the exact same thing, makes me paranoid of people or enemies that attack me at my 2-3 o'clock from my camera perspective.
Have you tried reinstalling the game? Running a file checker or the equivalent steam has to check for corruption issues?