48 seconds is a couple of miles or so, which makes the descent point roughly 13 to 14 miles out, 3 deg glide path makes platform height broadly 4000 feet agl 'ish'. Descent from 4000 to 530 feet in 48 secs! I think even I would have noticed a rather high (!) ROD and overspeed conditions.
Would somebody else like to try juggling the numbers and come up with a rational explanation?