Anecdote from my family:
My sister was unable to have any children. Very hard , in our big family.
She adopted 2 children.
No 1 was handed over at 2 days, and CLUNG to my sister. Good bonding.

No 2 was an open adoption, with all conditions set by birth mother.
My sister attended late pregnancy, birth, breastfeeding, then had to wait
2 weeks in a motel, while the birth mother prepared to hand over.
The handover was torrential, all crying, and my sister got the idea that
the BM would be back to get her baby at any time. The baby rejected
the bottle and his new mother OUTRIGHT, with back arching, screaming,
which she took personally, though now days, I could tell her about
nipple confusion, allergies etc. Very difficult to bond to this child,
and to ask for help in case he would be taken away. When deep depression
set in, the social workers supported, stopped some of the BM's access,
and presented the case at a conference. They diagnosed the baby's
problem as acute grief reaction. Things are calm and well these days.
Good attachment has taken place at last.
We've learned  about the 3 losers of the adoption triangle now.
Best wishes and strength to all parties.
Mary Grant.