I have only had my truck for about a month now and I had never put the off-road info up on the screen while driving around. I did today and my center and rear diff lock all the time. Pretty much every time I pull away from a light they both lock and my center will unlock a few seconds before my rear.

Is that normal? Does everyone else's Defender do that? I felt like my MPG was a little low and I'm wonder if this may be playing a part.

 

It is normal behavior

 

The differentials are infinitely variable and are always locking and unlocking based on driving conditions. This is how Land Rovers have been for about 20 years or so. Completely normal.