I have been struggling with these sensors for some time. First I connected on a board, described and everything was fine. Then I plugged in the installation on a dedicated wire and it also played, but after adding a new sensor one of the existing ones stopped giving a value. The sensors soldered in parallel, as the Grenton and sensor documentation stipulates, with a parasitic supply.
Connecting more sensors caused it to stop reading values from the existing ones,
but only some of them.
In the end, I bought a 5 V power supply and will be reassembling this already on a (non) parasitic supply until it works, I used sensors from two different vendors, each declaring them to be original DALLAS, but this was not confirmed with the serial number. The sensors are supposed to measure floor temperature, so the dedicated Grenton ones are moderately suitable due to their not very airtight design.