Not sure if this is a CUE error or not

I became a Type 1 diabetic while on active duty in 1997. I was subsequently placed on TDRL (which matured to a full medical separation). At the time, I was rated 20% for the diabetes. I was denied the next higher rating of 40%. The difference between the two is that the higher rating would have required restriction of activities. Apparently disqualifying you from military service isn't a restriction of activities.

Recently, on the advice of a physician, I filed for an increase and was granted. But while looking through my STR, I found an entry listing restriction of activities (other than military service) due to the diabetes.

So now I'm wondering if this would be a CUE case or not since the STR was obviously not adequately read, and it caused a significant difference in rating.