The M20E map I have (from my m&d who were helping on the elite start) is grey as well. It looks very odd against the M21E one I've also got which is fine.
yeah i actually wondered while i was running why they'd used a new grey symbol for the rocks?! then realised after that it was just shocking printing. No wonder I couldn't spot the tracks and rides!!
The dodgy thing is - it was just random maps. On a fair few of the W21E maps in the returns box, the black was fine (I could identify my grey one from the custom rip I put in it mid course ;)
That might explain why I could totally not see the rides to number one and wondered why I had a such a problem when I picked the map back up from the returns box later!