Sony WH-1000XM3 - v4.1.1 firmware failure?

GibsonSt19

Having updated my 1000xm3's over the weekend, there seems to be an introduction of hiss and a background noise of what sounds like distant traffic (even though I can hear nothing at all without the headphones on) when using Active Noise Cancellation, which was previously stellar. The potency of the noise cancelling is noticeably weaker since updating (I'd estimate around 40% less). Familiar auditory environments which were previously rendered almost entirely silent are now notedly audible. I've checked that the noise cancelling slider is left-most, and indeed it is.

I'm also disappointed to find I can't ask Alexa to play music from Spotify, and I press the button and just say "Play Metallica", it responds with "Shuffling music by Metallica on Amazon Music", yet nothing plays at all.

This update is very much a downgrade as it stands.

Anyone else with a pair of these, finding the same?