9.5 Months Odd Thumb Behaviour

[ELW85]

Hi all
I don’t know if I’m worried for nothing here (a lot of people seem to think so) but my DS occasionally tucks his thumb in and rakes at an object to kind of flip it about either in general or before picking it up.
He can easily open his hands and grab things first time using all fingers and thumb but he still does this for no apparent reason and I’m terrified it’s something like CP. any experience of this/words of wisdom?

I've not seen it before but they can all do odd things when they're learning.

Could it be his eyesight? Do you think it's ok generally?

@JiltedJohnsJulie - his eyesight is definitely fine. It’s like he’s consciously doing it. Maybe he is just learning?