Abnormal behavior
2021-03-25 08-15-21.rar (11.7 MB) 1Av7.3dm (53.5 KB)
run the command RemoveMultiKnot before piping. you have some stacked Controlpoints and Kinks leading to this effect. i did not download the rar but i can see the issue on the curve already.
Already tried, it doesn’t work
you should use it on the curve before you pipe it. here it then works as expected. if it still does not work in your exact usage of variable radi try MakePeriodic.
By me it only works with make periodic with the latest Rhino update 
Hello - explode the curve and make the smaller piece G2/curvature continuous with the larger one at both ends (Match command) then Join and try again.
-Pascal
Grazie Pascal, il problema l’avevo già risolto, ma non capisco perchè pipe non funziona (con match non funziona sia G1 che G2)