I havn’t looked at your problem closely but I think I’ve run into the same problem before and in my case it was because of a tiny difference in precision:
When there’s an alignment with curves and a profile that stretches over the whole alignment, the value for the alignment end station is calculated with a different precision than the value for the profile end station. The profile end station is usually one digit longer, therefore you can’t hook “Profile.EndStation” into “Baseline.AddRegion” without getting the error that the end station is not in the range of the baseline.