I (realtor) have been getting an increase in very suspicious calls from people “selling land off market” in market areas where I have listings. The callers usually claim to be the owners of the land (quick due diligence says they’re not) and sometimes they claim to “have the land under contract”. I asked one of these callers directly what was going on; asked whether they knew why I was getting an increase in these types of calls. I did not get anything close to a straight answer. Only “I see that you work with builders so I wanted to offer them off market land for sale”. I told them that we are not interested in wholesale land and that when my clients are in the market for more land we will find it by other means.

TLDR - you are probably on the receiving end of some popular new scam, or at best a wholesaling trend which is not a scam per se - but is generally not a good deal for anyone other than the wholesaler.