No question that the old favicon is being loaded on the 'void' page - In the <head> code its there. Very Unlikely a Cache problem if its happening for me as well.
All old Favicon sizes are replaced by new one of the same size: 32x32 192x192 & 180x180 - So its not that.
Unfortunately this is lilkely a problem you must contact Wordpress or your Hosting Provder with as its got something to do with the Favicon.ico file and your root directory.
Lay Theme is asking for this content and that is what your database is sending back - Going into the Theme editor and changing things with the Theme i would not suggest.
Sorry @save That its not a straight forward Lay Theme fix with this one! Contact your Webhost provider and ask for their help if you are able