Perhaps you maple set a lot of seed and it's getting rid of the excess so the remainder can ripen and drop in the Fall.
A lot of trees do that. Apples plums, etc.
Mike

Yes but inside the seed who seem to be dry, inside the seed it's green does it mean that the seed can grow or it need to be stratified (in a cold periodof time)

They may be dry - that is related to weather - but they will not be ripe. Ripe seeds are a factor of time of year only and June is NOT the right time of year. You can go ahead and attempt stratification but I doubt you will get much in the way of germination. And it is doubtful of any of last season's seeds would have remained on the tree over winter.

FWIW, a rather high percentage of seeds from named forms of JM are non-viable, meaning there is no live or fertile seed included in the samaras. These typically will fall early in the season but can also be held on the tree until fall and normal drop time.

OP does not indicate what kind of maple.
This time of year is the season for Red and Silver maple samara.