The agency probably knew perfectly well. I knew a couple who adopted two Russian brothers. The younger one was difficult but finally adapted, whereas the older one (7 at the time of adoption) was a fire-setter, violent and aggressive to the family’s other children and a thief. They found that he had something called “attachment disorder,” which is evidently very common among Russian orphanage products, and would probably never bond with another human being. They’re like feral children.
Because the couple wanted to keep his brother, they didn’t send him back, but he had to go into a residential facility by the time he was 10 and it cost them every dime they had to keep him there. I don’t know what has happened to him since.
Also, do you remember that horrible case in Connecticut, where two criminals broke into a families home, overpowered the father, raped and killed the mother, and then raped and killed the young daughters (by setting fire to the house with them in it)? The ringleader in that was a USSR orphanage adoptee (from I don’t remember exactly which country) whose US adoptive family had had problems with him since the beginning - fire setting, killing of pets, threats towards other children, convicted of serial house burglaries by the time he was 12, etc.
Whatever happens to them, they never seem to make up for those first few years in a Russian orphanage.