This whole situation with visual updates to Office is so puzzling and confusing. Same happened 4 years ago when they introduced this new "drawn" design to Office buttons/UI. Then it also was updating partially. Like my Outlook and Word had new icons, but Access doesn't and others were not getting same update.
Now with this refresh. It changed for me on my main work laptop in December. But the secondary laptop that i use occasionally, it still has old visuals (no new titlebar, old scrollbars). I use it not that often as main one, but still, it is getting every monthly Office 365 update (monthly channel) and it still doesn't get the refresh 5 months after the announcement. Same account, same org. This is abhorrent planning and deployment strategy by MS. Not surprising though. Most MS deployments are like that.