I think it has to do with the ecosystem. It seems like the meta data of S1 SLC is corrupted and might be related to:
and
I asked about it 4 days ago.
In the newly downloaded files snap fails to read the IW3, even though the tiff files are in the folder.
You can also see the boundingbox of the split dialogue does not fit the IW3, usually it would fit at least the corners.