Bring your gas bottle into the house tonight so it should be at room temperature tomorrow morning. When you put it into the van tomorrow try it straight away and see if it works ok.
There has been a debate on this for sometime as they put additional additives into gas for the winter to better handle lower temperatures - like an anti freeze, which they reduce in the summertime. If this is true then could this new bottle of gas be from the dealer's summer stock?
You can feel the liquid gas in the gas bottle sloshing about, which you won't feel if it was empty.
In the old days when they used to fill a small BBQ gas bottle, it could be easily over filled which didn't leave enough of a space at the top of the bottle to evaporise completely. It used to create all sorts of problems with our gas stove and fridge in the caravan.
Also gas bottles need to be secured in the upright position.
But if you managed 3 hours this morning, then I'm not sure what the problem could be. Are the ignitor batteries still ok?
Spruce