Morning Carol,
Sounds like this is your new BG?
First, if this is in fact Sherri's bird I would contact her and talk her through what has been going on. She has made a life with this bird and would know her best.
Second, It sounds like the honeymoon is over. What is that exactly? Well, ever heard of birds hiding their illness? They also hide their feelings in the beginning. They act calm and subdued to learn their surroundings before feeling comfortable enough to live in their surroundings.
Third, you can obtain years of information about a bird only to have it change in a new home. That once quiet easy going bird of 20 years is now loud and demanding. The bird that never said a word in one home is now chatting up a storm in another. That is extremely common and not a fault of either party.
I would first call Sherri and ask some simple questions. Questions that were probably not thought of. "what was her daily routine like?" Where did she spend her day? Was there music or TV? Did the house have a lot of action or was it quiet? Did you put her cage in an action area or too far from the action?
Even if everything is perfect she is allowed to change and you are to adapt. This could be a simple "time of year" with a bit of extra hormones. When I brought home Cha she decided to go into massive egg laying mode for which she never did in her 18 years of life. OR.. this could be her true feelings that she has chose your husband and you are the third wheel. I'm actually the third wheel with my BG, Korbel.
Life as the third wheel IS WHAT YOU MAKE OF IT. Your sweetie is making a new routine and you need to start RIGHT AWAY on how you are going to handle it. It will make or break you. Korbel is my baby, he does no wrong in my eyes. However, when given the choice between me or my husband he violently hates my guts.
( Yes, did all you other members read that? Shocked? I'm not... completely NORMAL ) While everyone is now remembering every video I have with my sweet Korbel on me, being funny and loving... yes, in a few hours he will love my husband and will wage flighted war at me.
Work/life balance is easy. Bird/life balance...
I ignore the unwanted behavior. I try to keep those aggressive moments calm and slow. When she lunges at the cage don't be dramatic with her, don't raise your voice. Calmly open the door talking quietly and walk away. Keep the routine you have in place as much as possible but make sure you are keeping yourself and your daughter protected. When she is acting up, don't scold or make eye contact. Just be aware she is watching your every move and wants a reaction. I walk away.
Korbel is my baby, always will be. We have a perfectly sweet loving relationship until we don't. Most days it starts when my husband sits down to watch TV at night. All of a sudden he gets this urge to want my husband and I become the battle ground. If I can do it with a flighted bird I imagine it being easier with a grounded one. While I could go on and on explaining I think having some feedback would help me target an area to start with.