Yes, so I have heard this. I’m wondering why proximity to the hub would make a difference with how it detects the device. I can see if it doesn’t detect it AT ALL but if it does sense the signal, shouldn’t it just always detect it the same either way??
if there is some occasional local interference, putting the device and hub closer together can help ensure the clean signal that is needed to add a new device to the network
it can improve the chances of successfully exchanging the encryption key, and so add the device at the highest security level it supports
it takes any repeating devices out of the equation, which again just gets you a cleaner signal when adding a new device to the network.
Basically, being added to the network as a new device is probably the most complicated process Any Z wave device will ever do, particularly those using higher levels of security. Multiple messages have to be exchanged in a set period of time.
So moving the hub and the device close together, or using a QR code to add if that’s supported by the device, both just simplify the onboarding process.
However, if you do do it this way (which is called “bench pairing”) then, after you successfully add a zwave device you should move it to its permanent physical location and then run a zwave repair to make sure that it will route through its correct neighbors.
Once the device is a part of the network, then messages can be routed through repeaters and if necessary retransmitted to ensure they get through. So that’s just a less fragile process than the initial adding of the device.