New Hayward Navigator Problems

We have a new pool with a exposed aggregate finish. We have used the Navigator three times. The first time was at pool school - it worked fine and we noted how far to turn the valves to set the correct amount of suction (we have a dedicated vacuum line)

We used it again a couple of days later to clean up a lot of sand off of the bottom of the pool.

I used it this last Sunday - I actually started it in the spa to get a lot of the sand out of the bottom - then quickly threw it into the pool. It didn't hit anything - and it appeared to be working correctly.

Today we tried to use it again - but it didn't crawl around. I picked it up (underwater) and saw everything moving - so I put it back down - but again it doesn't move - it just sits there. I double checked the setting of the valves - they are set correctly. Any suggestions on what is going on?