Open attached WaterfallBreak.ogwu in ORG-26281
select all and plot 3d waterfall,
open PD, go to pattern tab, change connect to B-spline, ok
open axis dialog, go to scale tab, from=0, to=2000
go to break tab, set number of break to 1, from 500 to 1500, ok ==> there is no fill under middle curve for 1st and 2nd plot
Fixed in Origin2023b.