There is a "fixed" or "base" price which is the price that will show in the search results and the price your listing will be rented at when the listing is beyond the 4-month "Smart Pricing" limit. Smart Pricing works for 4 months from today’s date. Beyond 4 months from now, guests will see your base price or the custom prices you’ve set.
If you have your "Minimum Price" set lower than your "fixed" or "based" price, the Smart Pricing can, based on the algorythm can reduce the price. Make sure your "Minimum" is set no lower than your "fixed" if you do not want it to fall below that.
So, for example, our "base" price is $50 but our Minimum is $43.
Also, double check that the room was not rented at your minimum and the price you are seeing is that minimum MINUS fees and taxes (if applicable).