App lock feature is not working due to Google security patch
App lock feature of particular apps does not work in Google security patch updated version.
(App lock; the function that protect personal information with pattern lock or password)
In this case, please guide refer to below.
As you can see there are two groups (①, ②) of apps.
In case of group ①, it is possible to enable app lock feature through phone setting.
In case of group ②, there is no way to enable the app lock. So app vendor must fix it.