Eye-opening Math Remediation Shifts at UC San Diego

I follow this stuff, and still this UC San Diego report is eye-opening

incoming university students increasingly required remediation of elementary and middle school math topics; in 2024, over 25% of these students had high school math GPAs of 4.0+ (???)
high school math grades do not appear to provide useful information and do not predict university math placement; correlation is r=0.25 (meaning high school grades explain only ~6% of the variation in placement, and students with similar high school grades often end up in very different placements)
analyzing all student data they had available, the best predictor of math placement was SAT math / ACT math score

$screenshotted portion of the full report; Table 1 and a highlighted quote$