I don't see that to be true as they'd have to come up with a damn good reason as to why you can't build a house on it. Of which I can't think of any. Once you've submitted your plans to the tessabahn you're good to go once you get the okay. I suppose different areas may operate slightly different but in general land offices ain't the same as immigration and their interpretation of the rules.
As a foreigner buying land in Thailand, you should only consider land that comes with a Chanote, Nor Sor 3 or Nor Sor 3 Gor. These can be sold, leased and used as mortgage collateral and are the only titles over which a registerable right of ownership or lease can exist. "More importantly, you cannot apply for or obtain approval to build on such land without one of the aforementioned titles. In any event, make sure you have a good lawyer look over the paperwork before you commit to anything.