Chalk this up to the variation mavens (Jim and Levi) at 707 Sportscards.
I can't explain how it might have been created, unless the signature portions of the 1954 Bowman fronts were the only elements of the cards' printing that were printed in actual black ink. Come to think of it, that might explan why the cards have such a pastel look to them.
It seems evident that the stray black loops that show up at the top of a few -- seemingly a very few -- Carl Erskine (#10 in the set) cards were once part of the Jackie Jensen (#2) facsimile autograph, and that the Jensen card must have been positioned above the Erskine on the printing sheet.
Out of curiosity, when I first got Jim's e-mail about this variation, I called up Carl Erskine 1954 Bowmans on eBay, both current and past auctions, and store offerings. Out of about 20 cards, not one echibited the black loops.
Realistically, as resistant as I've become in the past few years about adding vintage variations to the Standard Catalog of Baseball Cards, especially when most of them are just printing problems, I'd be quite inclined to accept the Erskine "with loops" as a legitimate variation, providing that more examples can be verified so that I am assured that this is not just a one-of-a-kind anomaly.
So, if you can provide scans or a photocopy of other specimens of this variation, please do so by adding a comment to the blog, e-mailing me at email@example.com, or mailing to Bob Lemke, P.O. Box 8, Iola, WI 54945.