Does the issue only occur on Netflix or across other channels installed on your device as well? If you haven't tried yet, you can remove then reinstall the channel. Make sure to restart your Roku device before adding the channel back in so the troubleshooting would be executed effectively. Follow the instructions below if you need help:
Remove the channel: Highlight the channel tile on your home screen and press the Star button to open the options menu. Select Remove channel and confirm.
Restart your Roku device: If it is inconvenient to reach the power cord to unplug your Roku device, you can restart the device from the settings menu. Go to Settings > System > System restart > Restart.
Re-install the channel: After your Roku device restarts, visit the Roku Channel Store and add the channel again.