Hi,
I have an issue which has been ongoing but hasn’t bothered me as I didn’t alter the design too much. Under Customisisng>Layout>Blog the headers for the settings are missing:
it looks like something is changing the theme customiser link colors.
It could be a plugin conflict which you can test by removing all other plugins. Let me know if it still an issue.
I finally managed to get around to looking into this, it appears that WP Coupons & Deals plugin is causing the issue. Hoping they can do something to fix this.