I have not needed to use REST Services to acquire a direct path to a specific service Portal in a while, but there is (apparently) a bug in ArcGIS Enterprise 10.6.1 that prevents a user from seeing their feature layer when trying to print from a web app in Portal.
I realize that there is a bug in version 10.6.1 (I'm in the process of upgrading, but that process is currently temporarily on-hold), but there is a workaround using a method I have used in the past with map images using REST Services.
However, I'm currently unable to see any feature services in REST Services (only Map Images). These feature services show up in ArcGIS Server Manager (services that the user can edit), but I need to get the path to the specific layer in REST Services to (apparently) bypass the bug that is preventing the user from seeing the layer when attempting to print.
Is there an ArcGIS Enterprise rule of which I'm currently unaware that doesn't allow feature services to show up in REST Services (i.e. only layers published as Map Images)?.