Baby Acting Different Around His Parents

You're his primary caregiver. It's like he's attached to you and not to them. He'll grow out of it and will do better for them once he's older.

I used to be a nanny and I experienced something similar. The parents of the baby were great parents, I need to add this, but there was something different going on at nighttime than the daytime. What it was, I cannot say. Maybe it is similar to how, when kids are older, they will do great for the nanny or caregiver and then fall apart as soon as mom and dad get home, I don't know.

I should also add that kids learn different habits and routines with different people. One baby I cared for had become used to sleeping in the swing for mom and dad, but I could get her down to sleep in her crib. Who knows why? That was just the routine I established with her. Do the parents have a simple bedtime routine to help cue baby in for that transition? (I always did two board books and three songs-- always the same each and every naptime.) Are the parents able to stay focused with the child through the entire transition time instead of stopping to check their phone or doing other things? Kids are great at figuring out ways to get their parents attention.

For what it's worth, when I did overnight jobs for that family, they were tougher and the baby was more needy in the evening when she was really tired.

Yes. Many babies are lovely during the day, and very irritable and cranky at night. Also, consider...YOU see the baby more then mom and dad does. (I assume you are full time?) He could just be more used to your way of doing things.

It's a really common thing.
In the afternoon or evening a baby that's been calm all day will just lose it and cry cry cry for usually a lot longer than an hour - but they still call it the witching hour.
Child is over tired and over whelmed and nothing seems to help settle them down again.
Someone once said: “It actually happens to grownups as well, which is why God invented cocktail hour.” .
What helped me was frequent walks with the stroller outside during the day.
Often our son would fall asleep along the way, but it was a deep restful sleep and that seemed to help to sometimes avoid the over tired scenario in the evening.
They do grow out of it eventually.

http://www.parenting.com/article/ending-the-witching-hour

Additional:
No, he's not more attached to you than he is his parents.
It's common for babies to be good as gold in day care but then be cranky and out of sorts when they get home.
At the end of a long day it's a lot of stress being good all day and when they get home to Mom/Dad they trust the parents enough to let it all hang out.
It happens all the time even up through kindergarten and possibly beyond.

Because kids are different in different environments. That angel in school can be a terror at home - different rules, different people, different reactions. He may also be tired, teething, etc. What do you do differently than they do? Do you know? Is there any advice you can offer? My DD's daycare ladies obviously did not nurse her to sleep, but I did ask what they did so I could keep that in mind on weekends.

He may be overtired.
Or teething.
Growth spurt, and at growth spurts babies get hungrier more often.
Or it may be all of these things at one time.
Or maybe the parents are stressed/tired at night and rushed... and babies do know "vibes" of people.
Or, because they are his parents, he "vents" in his own baby way, to them. And wants comforting.
Babies cannot talk. So, babies hence "fuss" or "cry" and this is their way of communicating.
And per a babies cues, then we try to comfort a baby etc.

Babies and kids, commonly are different for different people.

Seems he may be more attached to you. It could also be that once they are home they are trying to get stuff done and not able to "focus on him" and he's demanding that they do (in the only way a 7 month old can).

He may be responding to the parents. If they are tired or stressed, he will sense it and act out.

My daughter did really well during the day, but then come 11p would try and be up all night. He probably isn't acting that much different than when he is with you, just that you are awake so you don't mind paying attention to him. In the evening, Mom and Dad are in wind-down mode from work, tired, and just want some 'me' time.

I would suggest offering to stay late one night so that you could watch them interact, but that might lead to them wanting you to move in and be a live in nanny.

I know that some of my babies really have been different during the day and during the evening/night time, and that's just with me! My current foster baby is soooo easy during the day. Rarely fusses, naps well, is happy and smiles. But at night, she never wants to lay down, has a hard time falling asleep, fusses more. I've had other kids like this too. It usually evens out in the end.

He could just be fussier at night. My daughter used to cry EVERY night from 5:30 - 7:00. Didn't matter what I did or didn't do, she was going to cry. It was like set to a clock. Could count on it to start at 5:30 and end at 7:00. Was the worst 1-1/2 hour of my day!

After she outgrew that and I went back to work, she would start being fussy the minute I walked in to get her from the sitter. Sitter said she was great all day; no crying, but the minute I got there, everything changed. I just chalked it up to she was "telling" me all the things that made her mad that day. She felt most comfortable with me, so it was with me she just "let go."

Perhaps it's the same for this baby.