They are recommending you change the device's driver to a better fit.
In Hubitat, the driver is changed form the "Type" field in the device's "Device Info" tab page (see example picture linked here)
In that "Type" dropdown menu, all of the native drivers developed by Hubitat staff are listed. "Generic Z-Wave Plus Dimmer" will be in that list. After selecting that, hit "Save", then hit the "Configure" button (found on the "Commands" tab page [again, reference linked screenshot]) to ensure it's set for the device.
When adding a new device, Hubitat is usually pretty good at automatically picking the best driver Type for it, but sometimes there's a better fit available (like this case here).
ETA - added "Save" step per thebearmay's note below - thanks!
