Hello Yousaf,
Actually whenever you edit the “Features section” you have must change the Fontawsome icon from your “customizer” atleast once for every feature.
You may follow the below steps
Step 1. Go to Dashboard >> Appearance >> Customize >> Home section >> Featured Section
Step 2. Select FontAwesome Icon
Step 3. Publish it.
Kindly try and let us know.

Thank you.