Beech leaves fallen when still green. It happens every now and then. It happened last week. A strong wind blew; it was clearly felt on the open ridges, it was not easy to walk there. A stiff wind, from north-east; of the kind that clean air and give bright days, not so common in August.
But it is also not raining since quite long ago. Plants are stressed, especially where soil is thin and they can’t retrieve water anymore. Did you try to handle beech leaves ? They are thin, dehydrated. They fall much more easily in these conditions. So, it is enough a bit of wind to make them fall: especially the ones of the more exposed and stressed trees, that are almost defoliated.
And much more on the Apuanian Alps than on the Apennine. Because there soil generally retain less water. But also since the wind there fell down even drier after overcoming the Apennine range.