This problem sounds similar to a problem that I experienced. It could be caused by "double linking", i.e. an individual is actually linked to two sets of parents (adopted /biological?), or there is an actual duplication of these individuals.Duplication can occur if you import information from another file.
Record the RINs for the "wrong" parents that you see when you open the individual. Check to see if they match the RINs of the "correct" parents that you click on. If not, then there must be duplication of the individual in your files. Run a report of Duplicate Individuals (Print Reports - Lists). Be aware that if the surnames are spelled differently for two occurances of the same individual, you may have to go to the Options and try Soundex after you click "Duplicate Individuals" to find the duplication. Clean up any duplication by unlinking individuals and deleting the "wrong" entries, then relink individuals to "correct" parents, etc.