Odd streaking along sides of film.

I'm not sure what exactly could be causing this but I see it occasionally when scanning. I'm thinking it could be when developing but not sure how to prevent it.

I just mixed new chemicals and use a jobo 1500 series roller tank with a unicolor auto uniroller. I always pre soak the film before developing and have only recently seen this. I use the jobo plastic reels when developing. Could that be the problem?

If I'm looking at the right things, it seems like scanning artifacts. To rule this out, try rotating the negative when you scan (like 90 degrees or something) and see if the lines are in the same spots. If not, it's the scanning.

Also, it could be related to the negative holder of the scanner.

I would rather take a closer look at the camera. These streaks (assuming you mean the vertical lines near left and right image frame and horizontal lines near top and bottom corner) are visible in your negative preview, where the scanner does not yet have a concept of image frames. Until you reach scanning stage, your camera is the last device which does have a concept of image frames, therefore I would not suspect the development process.

If you camera allows it, try to remove the lens and open the shutter to see, whether film is properly pressed against the camera opening during shooting.