Your container compressed because the container was closed, and the cold temp caused the inside air to condense. Normal atmospheric static pressure then caused the container to compress.
As long as fuel is sealed, and kept out of bright light, temp. changes within livable temps. do not hurt the fuel. Now if you fill a plastic jug with cool fuel, then place it outside in this TX summer sun, well, expansion just may be stronger than the plastic jug. Wonder how I know that?? [&o]