For some Sentinel 2 griding tiles, there are no existing complete product that cover the whole tile (see https://sentiwiki.copernicus.eu/web/s2-products for information about the griding tile)
This poses a problem when trying to automate product retrieval for large zones.
Conceptual solution for now would be to detect when there are no complete products to be found, then select appropriate products and combine them to a mosaic. This however will not be trivial as there doesn't appear to be a consistent way of identifying potential products to create a complete mosaic.