Thanks Henrik.
The issues mentioned in the link don't seem to apply to the regular flows but I have found another which I run occasionally that had what appears to be an unnecessary "Keep device awake" so I have removed that and will see what happens.
While reviewing this issue I note that I have several "Delay" blocks which seem to have a default "awake". As these are generally short delays (say 15 seconds) the awakening does not seem necessary. However I note that the default seem to have it active. Would it make sense for me to normally NOT use "Delay" to awaken the device?
Hopefully your advice has helped me track down the issue, it will just take a while to prove it.
Mike