I have this duo in my novel, they're always together in chapters. Usually the story alternates between them within their plot, though mostly leaning to one of the characters, as he's one of the MCs and he's pretty significant to the plot and world.
Though, since they're so much together, they get a lot of attention also in the chapters they're not the POV in. That's okay obviously, but in the latest chapter, the attention almost completely shifts to one of them, who isn't the actual POV of that chapter.
The reason for this is that the other character gets drunk. They're on this mission, and the POV character has a more passive role in it. That narrative asks for more attention to the doer, but that's not in-line with who is the POV, and the center of attention for the beginning parts of the chapter.
So, is it okay to shift the POV as the chapter progresses? The chapter will end with the POV being the center of attention again, there's really only a little segment where the other character kind of takes over.
EDIT: When I meant who is active, I mean we see things from their perspective, because they are the one who is doing something. We see their preperations, even though the actual POV is not in the same room. And their emotions are described, not directly, but through surface level cues. So I would say it pretty safe to say the actual POV shifts, and it isn't a Holmes and Watson case. But as Galastel said in his answer, it is okay to shift POV, and it is really more of a question how.