Hi Sharif - when you do Loft there is an option in the upper-right options area called "Profiles:" and you have set it from the default of "Auto" to instead be "Exact" - when you do that the Loft will not do any refitting of the sections and will instead use knot insertion to make the profiles compatible with one another before doing the loft. That can sometimes be problematic with curves that are pretty similar yet just slightly different in their knot vectors, and also can have other difficulties on rational curves like exact circles and ellipses.

Switch the Profiles option back to the default "Auto" mode or to "Refit" mode and then that problem will go away and it will behave like it did before you changed that setting from its default.

- Michael