Is this something to be concerned about? Because it sort of seems like she hasn't learned much this year...or at least not what the Explore is testing? I just didn't expect the reading and english scores to go down and thought math might go up by more than one point.
I am adding my voice to the others saying that both reports point to the need for her to be taught at a higher level. I look at my two boys - both are good at math and both were tested on the EXPLORE in 4th grade. Ds1 got a 19, ds2 got a 25. Now, honestly, if I had to pick one as the stronger math student, I'd probably pick ds1. So, why the difference? Well, ds2 took the test in 3rd grade (albeit not through NUMATS), ds2 got subject acceleration in math, ds2 benefitted from some of the opportunities ds1 had (doing some of the problems that ds1 did as part of the math team this year)...
So, you might glance at these two scores and think ds1 is good at math, but ds2 is great, but that would be wrong. Ds1 didn't even own a calculator before he tested on EXPLORE, and his teacher at the time didn't believe in challenging him. It was probably a heck of a lot more impressive for him to get a 19 than for ds2 to get a 25 in the same grade. This is learnable material - your dd's high scores both years show a ton of potential- the English grade is pretty amazing and really shows that she GETS it at a very high level. But she can't learn this stuff by osmosis.
I'd go in and say, "hey, I'm paying for my dd to learn - she's already well above the average 8th grader but she's making no progress. She needs material at her level!"
I hate to say it, but she probably isn't learning very much because she probably already knows what they are teaching her. 
