Missing plone-compiled.min.js.map

In Chrome's inspector I see

DevTools failed to load SourceMap: Could not load content for https://devsite/++plone++production/++unique++2020-05-13T09:54:10.825507/plone-compiled.min.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE 

but rebuilding bundles, toggling develop mode, deleting things in portal_resources/resource_overrides did not generate the missing map file.

Where should I expect a generated map file to be served from by Plone?

It is very common that those resources are not available (I think, since I see it on my sites all the time).

Even Plone.org 'misses them'

that's an even worse sign

And trying to rebuild bundles results in terrible errors: the site has lots its Fontello font so all icons are gone.

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