ArcCalc turn up and down depending on zoom or/and pan

[Ruben DF]

Hi,

I am using OMArea to prepare a graphic based on OMLines which are straight and curves. To create the last one, I am using ArcCalc Class to provide lines with curves. I generate successfully the graphic, however, when I zoom over the map or I pan the map, the lines curved are turn up or down depending on the applied zoom in a random way, it is something very strange, any idea?If it is useful, I am using openmap version 4.6.5 (I don't know if it is a bug)

Thanks in advance.
Regards