Stability of deviceUniqueIdentifier

Hi,

I am using the deviceUniqueIdentifier from the SystemInfo class. The documentation reads "A unique device identifier. It is guaranteed to be unique for every device".

In my tests, I've noticed that this ID changes over time on the same Windows PC (at least one time, I suspect it was due to a Windows feature update). I am not sure if this is also the case on Android, where I'd like to use it.

My question: Does this mean, and should I interpret the documentation in the way that the device identifier is unique, but not stable? I.e. the guarantee is only that two different devices will not have the same identifier, but not that a single device may have multiple ones over time?

Or is this unintended behaviour on the part of deviceUniqueIdentifier?

Thanks,

Philip