Your DS18B20 temperature sensor is likely a fake, counterfeit, clone
This affects temperature sensors/parts bought from un-official distributors like ebay or AliExpress, not digikey, farnel, etc. Perhaps I've been too lucky in my career and practiced EE for work, but who would you ever go to ebay instead of digikey?? <mind blown><p>Digikey certainly has a premium, but their speciality is small numbers/cut tape/etc and they have a small order size which makes them ok for hobby work, and I've used them for small production runs when I didn't want to end up with a ton of excess materials.<p>Makes you wonder what other junk is out there, and what purchasing guy figured he'd save $10 and get it from ebay...?