@mattjarvisast I agree, sorry for hijacking your thread.
I’ve posted a new thread at DS1820 / OneWire library doesn't work on mbedos5, mbedos6 (NUCLEO-F303RE)
Thanks for sharing your working configuration.
edit: Problem ultimately solved by using a 20kOhm pullup instead, or using many (>=5) DS18B20 on the same bus.