Not having a FL model, I am guessing here, but I don't believe you have an air admittance valve in the bathroom sink. I believe there is a standard P trap and vent stack line in the wall. I could be wrong, I have been before.
More likely is the common problem of being prepped for a washer/dryer close by and hot having them. The water supply lines for the washer/dryer need to be flushed periodically as they can develop "skunky" water which you will smell at the sink.
Carl (n Susan)
There is more to life than fuel mileage.
2012 Montana 3700RL Big Sky Package towed by a 2015 Ford F350 6.7L PSD 4WD CC LWB