That’s pretty odd; I’ve just started trying to move my setup to 2.5.2; there have been some strange problems, and some caused by the move from Eclipse SmartHome; my recommendation would be to try this freshly compiled version of the binding; the only changes I made were those required to get it to build for the latest openhab version.
- do a bundle:uninstall on the existing weather flow bundle. This shouldn’t cause your items to disappear, but a backup wouldn’t be the worst idea

- shutdown openhab
- remove the old smart weather jar from your addons directory
- clear the caches as described at this thread: Clear the Cache
- drop this new jar in the addons directory: https://bitbucket.org/hww3/org.openhab.binding.weatherflowsmartweather/downloads/org.openhab.binding.weatherflowsmartweather-2.5.2-SNAPSHOT.jar
- start up openhab
Let me know how it goes!