That's what I'm starting to think. Maybe an inadvertant result of breaking the single rulebook into two?
maybe the designer will let us know, if not, safe enough to say it's grain. Good!
I like the separate rule books, but consolidation of the terrain charts into just
one 'very complete' folded chart would've been a good idea and in-line with the usual methods for these modules.
Mentioning that there
actually is grain looks to be necessary errata for both rule books. All we have to go on is the one terrain chart for this grain exception; this shouldn't be looked to supplant the rules, especially for another sub-module with its own set of rules/terrain cards that we had been relying on.