This occurs when a tendon profile point is not within the slab thickness. Profile values are always relative to the slab or beam soffit at the location of the profile point. The easiest way to find these problems is to look at a tendon perspective.

If a profile point is at a top or bottom surface step, RAM Concept moves the profile point so that there is no ambiguity. You should check that the profile point is within the expected slab area.