Nice to hear from you again!
1. This isn't an absurd speed for comprehension (though it is, of course, normatively extremely high). Two of my siblings were measured at that speed in childhood, and they both retain about as close to everything they read as one can get. And yes, this is probably her speed for second grade texts, though since the test is supposed to be adaptive, it is possible (depending on how the item pool is developed) that there were higher-level texts administered. Note it is possible that the winter scores are more accurate, not just demonstrating growth, if the adaptive testing software made an adjustment in her start point based on her fall scaled score. The fall test probably used the default second-grade-level start point (unless her teachers knew to make an adjustment), whereas the winter test could have been set to use her previous testing to determine the appropriate start point.
2. I don't know of any data that indicate that dysgraphia is more common in GT kiddos than in others, but it certainly is more asynchronous when it occurs. The gap between reading comprehension and written expression generally becomes more and more noticeable as the assessment products used by teachers become increasingly written ones. One hopes that some access to school services or accommodations will emerge from the eval results, if she is indeed dysgraphic, but even if they do not, you can support her continuing written expression development and enthusiasm at home by giving her access to scribing and speech-to-text for generating written products of her choosing. (Our DC uses speechnotes.co, which is free speech-to-text/text-to-speech webware, in addition to native voice-to-text apps on smartphones and tablets.)
There are quite a few families with 2e dysgraphics on the forum. I'm sure some of them will chime in shortly.
