I'm honestly on the fence on this one, it could be an optical illusion but it also looks kinda weird. Although since there are multiple angles that'd be harder for them to fake. Going with what we know about Biden's deteriorating mental state, it wouldn't surprise me that they'd pull this shit.
What also puts me off is how staged the questions and responses sound, like his handlers are starting to realize that a lot of people have zero confidence on Biden's capacity so they had to whip this up quick so he looks like he can take questions at least.
Honestly though it's kinda pointless to point this out even if it's a staged interview cause normies aren't gonna believe it. Try bringing up to anybody you know that they greenscreened Biden into a random interview and see how fast they call you a crazy conspiracy theorist that believe they did the same thing for the moon landing. Unless something else like this comes up, you're better off just letting this one slide.