An update to the above. I'm now very sure I had a bad batch of sensors, it turns out I'm not alone. Over people have seen the same thing having bought sensors from certain websites.

Be careful when buying 1-Wire sensors as it seems there are cheaper, not so reliable ones flooding the market.

Cheers

Mike

@reitinge

Již jsem problém vyřešil, problém byl v tom, že jsem napájel pouze Raspberry přes micro-usb, nikoliv Monarco HAT.

Vše funguje tak, jak má.