Hello There,
This isn’t a bug. You just have a different setting. A bug should be consistent when viewed anywhere. I recommend that if the settings of your staging is the correct, you can import it to the live site. Using the Customizer Manager in X > Overview, you can export the XCS file and import it over to your live site. Importing the XCS file to the live site will make sure that your staging and live site will have the same settings.
Please also check that your UberMenu settings has the same font size because the way I see, the staging is using 15px while the live site is 16px.
And another thing, in your live site there is a JS error on the page.
You may need to test for a plugin conflict that may have caused it.