Apparently pre-rinsing confuses the dishwasher or something. Not doing it leaves me with residue all over the other dishes though 🤷
Interesting. Why? Do the dishwashers there require only using cold?
In the US, it is always meant to be connected to the hot tap. The first rinse cycle doesn't heat the water (or doesn't run long enough for the heater to make it hot, anyway). It depends on the hot water from the line to be maximally effective that first rinse. And once drained and refilled for the wash, the water will get up to temp eventually, but it's more effective if it starts hotter.