This mostly happens in the presence of air. As long as the gas tank is tightly sealed, this isn’t an issue. I drive a BMW i3, I regularly have a tank of gas slo

This mostly happens in the presence of air. As long as the gas tank is tightly sealed, this isn’t an issue. I drive a BMW i3, I regularly have a tank of gas sloshing around for months with no issues. All of the plug-in hybrids run maintenance cycles every month or so to ensure that the motor turns over and some fuel goes through the injectors.