Scummy realtor behavior in hot market

[Wilson Hunter]

So I just had a verbal off market deal in place with a real estate agent in the Smokies who owns a lot of his own cabins (this is not someone who is active here!). I saw the property today while I was in town, agreed on terms (everything including days to close and earnest money), and he had me text him all my personal info so we could work up a contract and sign within the hour. I decided to pull over in a restaurant on my drive halfway back home to Virginia to wait for the contract to come in, and boom, I get a Zillow app alert that the property I had agreed to buy from this guy suddenly hit the MLS $50k over our agreed to price. I called him up, and he was basically like "I realized that I can probably get more, you can still submit an offer and we can see what happens."

This is my first foray into off market negotiations. Is this normal? How do people reputationally get away with this stuff?