[Sonos Ace] Audio and ANC artefacts since 3.9.9 FW update

Hello,

I noticed the following issues just after upgrading my Ace headphones to the 3.9.9 FW

Pop artefacts from the ANC when working on my computer, it’s related to the ‘click’ sound of my mouse and to the keyboard keys sound. I get that issue with Adaptative ANC ON and OFF (I’m aware of the well knowed ANC pop artefacts with some specific sounds, but this one only appeard after the update)
Audio artefacts when using aptX Adaptative in ‘low latency’ mode, it’s partially fixed by switching the bluetooth connection mode to “multipoint”, but i still get some artefacts from time to time.

I’ve already performed a factory reset, but it didn’t help.
Is there any where to downgrade the FW to the previous version ?

Thank you.