I just noticed this on oneworld.com explorer

"You can fly up to 20 flight segments on your trip. Travel between two points by surface transportation will count as one flight segment."

and I was trying to reissue a ticket over the phone and they wouldn't allow me to have land segments becaues it put me over 20 segs. Does anyone have any info on this? And does it apply to tickets that were issued before this rule change.