Crucible is inconsistent with redirects causing some Ajax to fail

See CRUC-7466 for original issue, I was able to reproduce the problem locally on 3.10.0 version:

• define site URL in your instance, e.g. http://fisheye.full.qualified.domain.name/
• ensure short name is resolved in your DNS (or /etc/hosts file), e.g. fisheye to same address
• you should be able to login to http://fisheye/ and load particular review (e.g. http://fisheye/cru/TEST-751) without being redirected to http://fisheye.full.qualified.domain.name/
• but once you click "Edit details" on review page you would get "The server is not responding" error. This is because AJAX call POST /json/cru/TEST-751/edit-details gets back empty 302 response with location header: Location:https://fisheye.full.qualified.domain.name/cru/TEST-751/edit-details/my-repo/ which is not being followed

Workaround

use the configured site URL always when using Crucible, restrain from using short URLs