We have a domain resolving to our AEM environment and we are seeing this issue.
A call using the domain "http://staging.thissite.com/page" will not retrieve the content at /content/site/en/page.html however we do get the site custom error page.
If the content has been cached previously using "http://dispatcher.url.com/content/thissite/en/page.html" then it will be served correctly using the URL above.
So our virtual host redirects are working and do point to the cache location but will not make the dispatcher retrieve the content if not already cached.
Our dispatcher logs are set to debug(3) but we are not seeing any entries except for the single call and a 404.
The one difference between the two calls that I can see is that during the 404 we are getting [publishfarm/0] and during a successful return we are getting [publishfarm/-].
We are on AMS in Azure. All Apache management is handled there. The process can write and does so for content retrieved from the front end URL.
Short URL is created by Publisher with mapping.
Using URLwith no cache:
[Wed Oct 10 07:56:17 2018] [I] [pid 62524 (tid 139782076208896)] "GET /content/bcbs/ecards/en/viewall/nutrition/healthy-lunches.html" 404 5378 27ms [publishfarm/0]
Using URL with previously cached content from the traffic manager URL:
[Wed Oct 10 08:00:20 2018] [I] [pid 61026 (tid 140152978441984)] "GET /content/bcbs/ecards/en/viewall/nutrition/healthy-lunches.html" - + 51ms [publishfarm/0]
Using traffic manager URL:
[Wed Oct 10 08:00:47 2018] [I] [pid 61026 (tid 140153163081472)] "GET /content/bcbs/ecards/en/viewall/nutrition/healthy-lunches.html" - - 0ms [publishfarm/-]
So is the issue identified by [publishfarm/0]? We have the domain in publish-vhosts.any and the custom 404 page from the site is returned.