Resources blocked due to MIME type mismatch (Caddy)

Trying to access a newly setup instance from latest Firefox, seeing "Loading Funkwhale..." forever with multiple messages like this in the console:

The resource from “https://DOMAIN/front/js/chunk-index-vendors.ca8affd0.js” was blocked due to MIME type (“text/html”) mismatch (X-Content-Type-Options: nosniff).