For any ingress that uses a non / path e.g. /myapp, trying to hit http://<host>/myapp results in a 301 with an incorrect Location header. Hitting /myapp/ hits the backend as expected.

HTTP/1.1 301 Moved Permanently
Content-Type: text/html
Date: Fri, 14 Dec 2018 12:11:47 GMT
Location: http://shin-test-ingress.<domain>:8080/myapp/
Server: nginx
Content-Length: 178
Connection: keep-alive

The 8080 is the port nginx is configured to listen to rather than the listening port of the ELB.

Arguably, hitting /myapp shouldn't be issuing a redirect at all; it's the implementation of

My guess is that it's failing to find an exact match so it fallbacks to an approximate match, finds it but then thinks it should issue a 301 to the path it's found.

Historically, most endpoints in feed have been APIs and this was only noticed when someone tried to use a path with a website and a browser although in practise, we tend to just use / as the path if we're fronting Grafana, Jenkins etc.