As anonymous user:
I guess it must have something to do with caching, perhaps it's even specific to the environment or nginx caching, but this is crazy:
https://julian.pustkuchen.com/de/jtl-shop-5-seitentyp-pagetype-hook-140-...
opened for the first time in a fresh browser or incognito shows "Access dened".
Pressing Strg+F5 shows the page.
For me it only makes sense, if the browser passes a header to the proxy to skip its result and return the actual result, but don't store it...
What the hack... We should have a look if we're doing something wrong or now.
Postponed
2.0
Code
Clearing the nginx reverse proxy cache on the server solved the issue, but still the reason could be that we're not returning cache headers correctly.
Anyway this will be super hard to investigate so for now let's postpone this and see if there are future reports and details. Or anyone finds a related bug in the code.