I discovered while editing some photos that half of the scans had a purple streak across them, a little bit below the top edge of the image.
It appears to have been a random SilverFast glitch. I use SilverFast 9 with an Epson V600 scanner, which scans twelve frames at a time in two rows of six each. The affected photos were the lower row of each pair.
Scans before and after that roll have not been affected; neither the other roll I scanned the same day (I quit and relaunch SilverFast between rolls due to its memory leakage), nor the rescans I'm doing now.
📷 Canon EOS Elan II
🎞 Fuji Superia 400