side by side tray not completely filling with water

small cubicles in ice tray are not all filling with water only first 3 are what is wrong everything else works good freezes good dispenses good

The top spray arm on my Frigidaire dish washer is not spinning. I have cleaned the filter twice and found a lot of soap scum/debris. It sounds like it is running fine, but every time I open the door to see if the top arm is spinning it is in the same position. Any suggestions? Thanks!!