It occurs that if you marry a daughter her children don´t inherit the name of their father. They just get random names. If these children coming out of age and getting married the surname of their own children is inherited correctly. It only happens to sons. For daughters there are always random names.
So can you please fix this so that the first generation also get the name of their father? I think it is somehow connected to the fact if the father was born in your Family tree . If he is married into your family it seems not working properly.