Files not appearing in scan folder

This appears to happen more frequently with copiers and other devices scanning to SMB shares, where a scanned document does not appear in the folder for several minutes for the end-users, however on the server-side it appears instantly.

Browse to the registry key below on the workstation, create a new DWORD value called DirectoryCacheLifetime and give it a value of decimal 0.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\LanmanWorkstation\Parameters
 DirectoryCacheLifetime = 0

Alternatively, you can create a group policy to set the registry using

Computer Configuration > Preferences > Windows Settings > Registry

directorycachelifetimegpo

Additional info: SMB2 Client Redirector Caches Explained