MZD Commander Knob won't scroll

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2018 CX-5 Sport Nav+
Anyone seen this on a MK2?

I've got a problem with the commander knob - on startup, 5/10 times (and more regularly now) the knob itself will not turn to scroll through the menus. It 'feels' physically fine, spinning with the indentations but there is no response. All other buttons, the knob itself can be pushed up/down/left/right and the volume knob are always fine.

There's no pattern to it - but when it fails to work, it tends to not work again until the next day no matter how many lock/unlock cycles or short trips have passed.

It can't be hardware as it would fail during driving, it either works fine from boot until shutoff or doesn't? I've performed multiple reboots and a few factory resets but this doesn't seem to effect it's current 'state'.

This is on a 6 month old Sport Nav+ with Mazda-installed CarPlay, on latest firmware. Dealer yesterday said there were no codes showing and they couldn't replicate the fault, of course it was fine this morning and getting into the car tonight it's broken again. There is no difference if the phone is plugged in or not.

It's booked in again on Monday, anything I need to be telling them to concentrate on?
 
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