Switch doesn't play JoyCon Connection animation

[Calvin]

I have the same issue on a Switch beside its 2101-0001 error:

M92T36 replaced still short on VCONN_IN

Thank You, Dallas. It was a good hint. I found corrosion at two pins at the right Joy-Con rail. After cleaning both rails both Joy-Cons are working plugged and wireless. Only the ‘Plugging’-Animation for the right one is missing.