It appears that some Z6 & Z7 units are being recalled for service, to fix a IBIS problem. Nikon is doing this at no cost to the consumer - they are also paying for shipping both ways.
The US page is not up yet but you can check the serial number of your camera here - https://www.nikonimgsupport.com/eu/BV_article?articleNo=000042596&configured=1&lang=en_GB
to see if your unit is amongst those affected. It appears that mine is not.
Cheers!