It wasn't 54.4°C though! The original value was only 130 °F which is probably between about 54.2 and 54.7 °C but somebody made it look more accurate during that

It wasn't 54.4°C though! The original value was only 130 °F which is probably between about 54.2 and 54.7 °C but somebody made it look more accurate during that first conversion which fooled you with the very thing you're saying is OK. You're bound to sometimes lose information doing round trip conversions no matter how many digits you have so don't do that if you care about keeping as much precision as possible. The Guardian reported it as 129.9 °F because they converted twice!