I have it on the hub and all works fine in manual mode - motion, dimmer, off/on etc.
On/Off works in Smartthings app (not classic) except for dimming. When I try to dim this error appears “A network or server error occurred. Try again”. If the device is off on smartthings, moving the dimmer does turn it on to full power 100% regardless of whatever level it was set at manually prior. There is probably nothing to do and I’ve never used nor want to use Classic.