The so called Alternate 4th Edition was a parallel print run to 4th Edition. It was not produced by the Belgium printer Carta Mundi but the United States Playing Card Company (USPCC). Alternate 4th Edition cards don’t show the standard circle pattern but vertical serpentic lines and do not glow under black light due to a glossy UV protective coating.

This version of the Magic back had been used for rulebook covers etc. only up to this point, possibly it was accidentally transferred to the actual cards. The top right corner of the A in MAGIC  is dark, whereas it is lighter in normal cards.