The issue existed in Polar, Smith and Radar Chart since at least Origin 9.0.
Open Plot Details (PD) dialog, go to layer’s Size tab, set Height to 50, apply ==> size is not changed, the graph move to top, note top is 11.74
ok with PD, reopen dialog, go to size tab ==>Top is -0.2641
Fixed for Polar and Smith Chart in Origin 2023b. But too hard to fix it for Radar chart. So the issue will still exist in Radar Chart.