As of today I've started noticing that my Nokia 8 sometimes won't react if I double tap on its screen to wake it up... It takes maybe like three tries to wake it.
Sorry I have no solution to the problem. All I can say is I have had this issue from day one with my Nokia 8. Compared to my previous BlackBerry Priv, double tap to wake implementaion on the Nokia 8 is poor and often requires a number of attempts.
We stand a better chance of praying to the tooth fairy to fix it than HMD doing it.