Search glyphicon disappearing

I am modifying Bartik into a new theme called Opal, and everything seems to work so far except for the search glyphicon “magnifying glass” symbol. It appears if I place my new theme back into 8.x core — mysite.com/core/themes/opal — but when I place my theme in the proper root directory, mysite.com/themes/opal, it disappears. Any advice would be most appreciated. I can always just spare the Opal folder in core when upgrading, but having it work in the proper folder would be better.   

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