HLS S30 - Multiple Sentinel-2 acquisitions the same tile on the same day?

[juliederey]

Hello,
I noticed that for some tiles and dates, there are multiple Sentinel-2 acquisitions available in the original ESA archive (from different orbits), but only one S30 granule is produced in HLS for that tile/date combination.
For example, on February 19, 2019, for tile T31TGK, the ESA archive contains two Sentinel-2 acquisitions (at 10:30:53 and 10:38:24) that are spatially complementary — one covers the northern part of the tile, the other covers the southern part. However, HLS only provides one S30 granule that covers only the northern portion, leaving nodata in the south.
My questions:
What are the selection criteria used by HLS when multiple Sentinel-2 acquisitions exist for the same tile on the same day?
Is there a minimum spatial coverage threshold required for an acquisition to be processed?
Why aren't complementary acquisitions mosaicked together to maximize spatial coverage?

Thank you for your help!