This is because, due to a patent that GE didn’t pay to license, those switches do not send out “status” updates - they have to be polled. So when you send a command, HA then has to come back and poll the switch to get it’s current state. The default dim/ramp rate for the GE switches is a little slow and so when HA polls, it hasn’t quite reached the commanded target.
So, what you do is in your zwave: composnent in your configuration.yaml file is you set the refresh_value: true then delay: to how ling HA should wait before asking the switch for its current state. Here’s an excerpt from mine:
zwave:
usb_path: /dev/ttyUSB0
# add refresh delays for the GE dimmers
device_config:
light.living_room_lights:
refresh_value: true
delay: 2
I also changed the ramp rate through the Z-wave config panel so it’s faster. If you have left them at their out-of-the-box values, then you might want to make that 3s as I believe their default settings have them doing single-steps at 10ms intervals (so going from 0 to 255 - off to full brightness - would take 2.55s).