Notice the two cut labels, should have been "Piano di Mommio" and "SR439".
This is happening because by default Mapbox Styles allow labels to cross tile borders:
And there is a lengthly explanation of why it's done also in the code:
Except that the output above is not acceptable... and I believe we should just ignore the setting, because
the context is just not the same. In client side rendering, a label will not be cut, it can still be painted fully,
worst case it's going to overlap with some other labels.
Server side instead, there is no setting to force the appearance of the label in the other tile, they are produced
independently and are working against different geometries (clipping).