This has been tested on two machines running Ubuntu 16.04 LTS, using the "Mono JIT compiler version 4.2.1 (Debian 184.108.40.206+dfsg2-7ubuntu4)" (per `mono --version`) - the latest version available via `apt install mono-runtime`.
We're depending upon the FileSystemWatcher to catch files being dropped into a specific directory, however FileSystemWatcher is not firing either the Created or Changed events when files are added to the directory being watched.
After a bit of testing, we have found that the FSW will pick up the files, so long as the files are on a storage medium local to the machine running the application; if there's a network connection involved (ie the directory in question is on an NFS mount or a CIFS mount) then nothing is fired at all.
We're able to work around this utilizing a repeated polling of the directory, however I still felt the bug needed to be reported. Seeing as there appear to be other versions in the version selection newer than ours, there might be a chance this issue is already fixed, it's just not available on Ubuntu 16.04.