Thanks for reposting. I deleted your previous images from the first post when I couldn't get them to show up. (Thanks, Brian).
Maybe Gang will have some comments about that method, but the usual cause of high correlation is motion. Without censoring motion, that is pretty likely. After censoring, it's still possible depending on the thresholds for motion and outlier limits. There can be other significant artifacts too within the signal. Here, the seed time series is the same for both sets. Is that seed data pre-censored? If it is, then the pre-censored and post-censored data won't correlate.