Have seen others with this or a very similar issue. After updating either Wordpress (4.9.6) and/or Laytheme (2.5.5) today, my Webfonts disappeared from my site.
I noticed after reverting to a backup, that the /fonts folder inside (public_html/wp-content/themes/lay/) from my files has been wiped. Strangely, this can't be added back in saying that it already exists.
A resolution for this is to:
Make a new fonts folder (with a different name) and add files back into:
Update the link tag in Webfonts > Font manager
Admins, do you know what the cause of this is?