When using @now to format views/columns using JSON the date is taken as the US style (mm/dd/yyyy) regardless of the regional settings of the tenant. It would be useful if it either uses the date format of the tenant, or allows the user to specify the date format. For more details of the problem see here: https://social.technet.microsoft.com/Forums/msonline/en-US/21712788-fafa-4898-9cee-897d1b3afb88/modern-list-view-formatting-with-uk-dates?forum=onlineservicessharepoint