I understand that, but the opponent was still trying to crouch after the J.B and the counted as an overhead as noted by the red exclamation point. I was wondering of it would still count under those circumstances. That said, I may have mis-read the mechanics behind it.
EDIT: Ok yea, it is a Fuzzy Guard, because the Ragna went to crouch after J.B and got hit by J.A when trying to block low. It doesn't matter if the move normally whiffs or not, if the opponent tries to go from 4 to 1 after blocking a jumping normal, the second hit should hit them if they try to block low.