404 fallback only hitting 2/3 upstream sets

[helliax]

Thanks for heads up, Maxim. In what cases would it go into an infinite
loop if I left it outside? I had thought that "location /" would catch
all requests, and setting 

proxy_intercept_errors off 

at the last handler would break the chain by returning whatever upstream
setC returned?

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,229402,229466#msg-229466