The thing with Pintsize is that, unlike the other AIs, he isn't really treated as a person. Doesn't really invite it, either.
Like, take half of Pintsize's shenanigans, and imagine, say, Steve was doing them. Or some other adult dude. Can you imagine the group continuing to tolerate his presence? They'd kick a jackass like that to the curb and never speak with him again.. Instead, they react to him with eyerolls and occasional violence.
The violence is also kind of part of it. If you have someone in a group who you regularly felt you needed to literally throw into a wall, you'd probably think something was wrong. Sure, he's a tough little robot who can be put back together, but it still apparently hurts.
Again, imagine he was a human. You have some dude who regularly harasses the people around him (sometimes sexually), but it's "justified" because the cast members beat him up, or duct-tape him to the wall, or what have you. It's a fairly unhealthy dynamic.
This made a bit more sense early on in the strip. AnthroPCs and other AIs had very simple, somewhat innocent personalities. They weren't really responsible enough to be treated like adults, but weren't really children either. Now, both individually and as a group, AIs have matured as time has gone by, especially as Jeph has deepened his worldbuilding and storytelling. The world is much more complex than it was. But not Pintsize.
He acts like he's the same mascot/pet he's always been, rather than a person who's responsible for their actions and how they impact those around them. Early on, most AIs (generally AnthroPCs) acted similarly. Not in the same way as him, but not like responsible adults. Winslow and Momo are good examples. It's significant that both of them now have full-sized, fully humanoid bodies as they've accepted more "adult" responsibilities.
Now Pintsize is faced with a world that's changed, and he hasn't changed with it. He might worry that he can't. He's showing some understanding at times that his behavior isn't acceptable. That they aren't just harmless shenanigans. But I think he's also uncertain about whether or not he can change, and whether or not he can face up to his old self. Becoming an "adult" means facing up to all of the things he's done, accepting responsibility for them. So he tries to cement his non-person position by deliberately rejecting responsibility for his actions.
I could be reaching here, but I feel that there's more of a performative, theatrical nature to a lot of his more recent stunts; that he's doing them specifically to keep people thinking of him as the same ol' Pintsize. Pintsize, that goof. With his shenanigans, and wackiness. He's like a cartoon character, or a naughty little puppy who can talk! He can't help being him. I think a lot of the cast accept him that way because that's how they've always known him (and it was unusual for most people at the time to run into AIs who weren't at least a little bit like that). Others, like Claire, accept the dynamic because they want to be part of the group. Winslow and Momo disapprove of his actions, but they also "grew up" with him, and they're desensitized to him.
Bubbles knows better, and she's never had a reason to think of him as anything other than another fully-sapient person who should know better. She's from outside the social circle, so she doesn't have preconceived ideas. I expect that she'll continue to call him on his jackassery.
I feel like Jeph's setting things up for some character growth for Pintsize, and I'm looking forward to seeing where he goes with this.