I was watching a YouTube video, below, that featured a 752 landing at LGA. If you watch between 37 seconds and 40 seconds, you will see the spoilers retract slightly and go back to full deployment. I've actually noticed this on my flights on 757s before too. I'm trying to think why that would happen, but being not technically literate as such I would rather ask here. I was thinking along the lines of either the deactivation of the autobrake system to go to manual braking, or the reverse thrust system being taken off. Anyone with insight?