Inconsistency in Anathem

General spoilers for Anathem I suppose.

I'm currently rereading this, or technically listening as audiobooks are the easiest consumption mode for me at present.

Anyone that's read Anathem will be familiar with the deliberately invented words for common things, which I take as being to keep the reader off-kilter about the nature of Arbre and not think of it as Earth. For vehicles, there are three levels that I see:

• "mobe" - a car
• "fetch" - a pickup or van or any utility vehicle that isn't a truck
• "drummon - truck including semi trucks and so forth

All of this is fine, but suddenly, in Chapters 6 & 7, there are a couple of mentions of trucks and then it's back to drummons again.

Did Neal do a find-and-replace for truck->drummon and miss a few? 😄