Upgraded twice from 18362.239 offline, upgraded from 18362.267 offline and then tried online with same results. The store App and all related apps, Calculator, Mail, Feedback Hub and many more are gone. This was on a total clean install of 18362.
Next tried again in a different vm upgrading from 18362.267 with exact same result.
Build 18945 did clean install with all Apps properly without issues. Several attempts at upgrading from Release, different vm's, all with the same result.