It's sad that adoptions tear apart families.
Yes some matches can be further back than predicted or should you share more than one ancestor could appear closer than they are. Further matches back wont help an adoptee if they dont have their birth parents names. This is why ancestry needs to release raw data. We have a lot of illegitimate in our tree. Most of my bio family are accepting of this. I even have cousins who have several NPE like we do' Its our American Indian lines. All the tribes practiced polygamy and we got lots of it. It was their culture and some who are religious have issue with all the NPE and polygamy. We have one family member that has a 1700's bible we need and she wont give it to us because one of my cousin lines had 8 children out of wedlock and she put them in the bible. This person wont accept cousin line came from a different culture and this cousin line is out in the open with court records that all her children were illegitimate. She was being a kept woman by a wealthy married man.
Like I posted before people need prepare themselves before you DNA test you might get surprises