Hummingbird: Minification issues

When Asset Optimization is enabled, the Menu color changes, as shown in the following screenshot:
https://static.livechatinc.com/8801096/PACS5Y2LG6/3f0880e5a324431d5edde90a0738ab73/Screen%20Shot%202018-06-23%20at%208.53.13%20PM.png

Looking for a workaround to fix this via Asset Optimization settings. Please check the chat notes for more info.