Set up my new Shield last night, mounted my nas and pointed Plex at my folders there. I set the libraries to update when something is added and also have it to update hourly. Early this morning something was added to the folder but Plex didn't pick it up. I had to manually refresh library to see it. Anyone else have this issue?
The automatic detection uses operating system APIs to be alerted to changes on the hard drives. As a rule (with exceptions) Plex won't be able to automatically detect changes in a library on a NAS or remote share. There are workarounds where people have created scripts and such to push the API to the PMS machine, but it isn't feasible for an average user.
Setup periodic scans as an easy solution.