Hello Simon,
Where you find duplicate L1C Tiles, it is because your product has 2 (or more) Datatakes within it. In your first instance (Orbit 002973 over Queensland) both Datatakes were processed at Svalbard (SGS).
In your second example (Orbit 003668 South of the Equator in Brazil) the L1C Tiles come from Matera, Italy (MTI) and Svalbard (SGS).
In the second instance, I’ve done a rough approximation of a single L1C Tile (20MNE) on a Catalogue view containing the Orbit 003668
You’ll see how the L1C tile sits across the line identifying separate Datatakes.
Cheers
Jan
S2 MPC Operations Manager