2OLDMAN - You know I have just started to see this happening here. Wondering if it is something with the summer gasoline on the market now. Two much corn syrup maybe...
I've been carrying my generator gasoline in the plastic gas can tote under my hard plastic folding bed cover for years and never saw any of this. I first noticed this about a month ago with the sides of plastic can sucked in very bad... Even after I released the cap it sucked in air but still didn't fill out the can until it sit for quite a while. Sitting inside the garage the gas can doesn't have any these problems at all...
A mystery here as well...
Roy Ken