I'm having some difficulty sometimes creating relations between a 3d sketch spline and a curve feature, like a helix. Sometimes it works and sometimes it doesn't. The relations would be between and endpoint of the spline and the end of the helix, or an internal point in the spline and the helix itself, or a tangent between the spline and the helix.

Has anyone else had this difficulty? Did you figure out what was causing it? if you have any info on this, I'm all ears.

I'm using sw2020sp1