I'm using 3.5 and I am having issues with the mouse cursor. It keeps trying to move off in a random direction at a really slow speed. I have to reposition it a few times in order to make it stop moving, however it's really annoying when I am trying to click on small items such as blouse buttons, menu items. It also results in the player character rotating to the side involuntarily when engaging in a sexual position.

Any ideas on the issue?

This could be a local issue. Are you using a wireless mouse?
This may cause a jerky effect.

No, I am using a wired mouse. Always have for that reason. Not experiencing any issues whatsoever anywhere except in this game. It's not jerky, it's a smooth motion of the cursor heading in one random direction.

Sounds like something you'd see if you have a joystick plugged in too and it's slightly off centre or not calibrated.

I have a game pad plugged in sometimes but I experience the same issue with or without it plugged in. Here's a GIF image of what happens:

http://gfycat.com/InconsequentialLeftElephantbeetle

I've only ever had this issue once before and it was on a huge commercial game. The fix was adding a line to one of the .ini files in relation to mouse movement but I don't remember what it was.

You could try setting cursor = true in the display settings (settings.ini file).

That will let the software use the windows cursor.

Still hasn't fixed it unfortunately.

I'm having this problem too unfortunately. Not sure if there is any way to combat it. I'm surprised I'm also not hearing more people talking about it.

It's not a common issue here and likly not at all caused by the game. I've had this issue in the past with games using my R.A.T 7. But not with this game. Sometimes high DPI mice.. meese.. mouses..(You know) are hypersensitive and can get a bit fucked by minor settings or a single flake of dust on your mousepad. Whenever i had this issue i'd make sure i had all mouse acceleration setting OFF, in my windows settings, browser hardware accelerators ect ect. Than i'd turn my mouse dpi down to something "normal". This worked with most mice, but not the RAT, that fucker had to be put down lol. I now use a cheapo $30 logitec mouse and have no issues ever. My $100 Rat is a backup mouse that never leaves the box.

Do you have a 2nd mouse, trackpad or drawing tablet plugged in?