First let me begin by saying this. Pleasseee don't think I'm being judgmental, I'm not, but responses via text can be interpreted incorrectly. Second, this will probably be long.
He probably was super friendly and "cream of the crop".............. at the sellers house. In the environment he was familiar with, where noises and voices smells and routines were normal to him.
Gliders can and do behave differently from one home to the next. They can be sweet and calm at one house and a living terror at a new house and vice versa. They can become total opposite of what they were at the prior home.
Take a moment and try to see things from his perspective. Everything he has ever known has changed. House, humans, cage, cagemate, food, sounds, smells, other pets, pouches, toys, routine... I could go on and on but hopefully you get what I'm saying, it's overwhelming to most gliders.
And this new person has had you for 4 whole days... and expects you to be a glider your not, that's a pretty high expectation to have on any glider. His cage mate helps comfort him some but he's new to him too. You can't compare the two they aren't the same, each glider is an individual and are going to behave differently.
Now put yourself in his place, some giant human just took you from everything you ever knew and made you feel safe and plunked you in a room with some stranger, you couldn't escape and everything is new,. Would you be scared? terrified? mad? untrusting? Do you think the giant wants to eat you for lunch or mean you harm? what are you doing there? what does the giant want from you? where's your family and your favorite toy????
I also once thought a 2nd glider (Simon) should be easier, I was horribly wrong. My first glider was a breeze, my second took 6 months, lots of work, and a strict routine, to even start being comfortable on me.
I learned a lot of things from Simon but the major thing was not to place expectations on them, for anything.
Expectations are the sure fire way to be disappointed.
Get to know Jinx for who he is, and don't expect him to react to things the way Buddy does.
Understand that YOU may need to do things differently with Jinx than you do with Buddy. Rather than expecting Jinx to adapt to yours and Buddy's method.
I have 3 cages of gliders some I got as adults, some I got as joeys, some were born here. Every single glider is an individual and I've had to change how I do things accordingly with each one as I learned what each one needed. Some were easy like they been here their whole lives, others took time, work and understanding. ALL were worth the effort and the reward far outweighs to work.
Simon was probably the most bonded to me glider before he passed. He had to work just as hard as he made me work. And believe me, he didn't make it easy lol I was afraid of him at first as much as he was afraid of me.
I expected him to be easy, I expected him to accept his new future, I expected him to love us. He expected us to be neglectful, he expected us to ignore him, he expect to not be loved.
We were both wrong. But it was the most beautiful transformation and friendship when we both worked passed all of that. I trusted him completely and he trusted me just as much and then some.
I also have a glider that was born n raised here, to ME she IS the cream of the crop, quiet, and naturally mellow. Right up until I hand her to ANYONE else lol
I never heard her crab even once until I handed her to a local friend who also has gliders. She was fine for about 2.3 seconds and realized she wasn't on me. The crabbingggggg that ensued omg you'd have thought Courtney was holding her by the tail or something !! as soon as I took her back she looked at me and looked at Courtney and back at me again like wth mom!!
Her reaction startled me as I'd never seen her act like that. I just assumed she'd be mellow and calm on Courtney like she is with me. Poor thing about came unglued lol
So you see, you are not alone. It's actually a very common thing what your feeling and going through.
So just pause, breathe, regroup and try to stop having expectations and comparing one to the other. Give him some time to adjust to all the new things, sights, sounds, smells etc... he will come around and start to get used to the new routine.