jaapjansma
commented
2 years ago @pbatroff told me there is workaround:
Change the mosaico_tpl directory to [civicrm-files]/persist/mosaico_tpl/ then put a template (named differently) there and use that. Background is, that in the persist directory the URLs will be corretly changed, since images etc are located there as well.
Fixes the replacement of the social media icons from Mosaico templates. Requires additional configuration of civiproxy (a url to the mosiaco extension on your civicrm installation).