Are the file mounted to your OH server in a CIFS mount? I experienced that problem as I had my config files on a shared folder from my NAS. Turns out that CIFS at least does not generate the file events that OH 2 relies upon to know when a file has changed.
When restarting openhab or reloading the core via Karaf console with bundle:restart org.eclipse.smarthome.model.core everything works perfect. No warnings or errors regarding the config files can be found in the logs and all changes become active.
Currently I run openhab2.1 just as a test system on my desktop PC. Live system still is 1.8.3 on a pi2.
Config is not mounted from a share. OH is manually installed to /opt/openhab/openhab2 and all config files are located there.
Hope this helps. If you need any further information just ask.
just want to give you an short update. It seems to work now.
Not sure what exactly was the reason. Only thing I changed was an update for visual studio code and the oh extension.
So I think it could be related to this issue
I experience the same issue since I have moved my root to a USB-Stick (using Raspi2 with micro-SD).
The strange thing is, that it works right away with changing the sitemap and rules, but not the items file.
EDIT 1: bundle:restart org.eclipse.smarthome.model.core
did help and the systems works as expected.
After restarting I get a warning though: Cannot customize folder watcher for folder '/etc/openhab2'