False positive functionality not working

[dicksnel]

When marking an issue as a false positive, the API call results in a 404 and the changes are not saved:

In the browser console, the following API call QT makes results in 404:

http://www.quality-time.xxxx/api/v1/measurement/xxxxxxxxxxx/source/xxxxxxxxxxxxxxx/entity/10062:359:13:3:GET:https://xxxxxxxxx.org/aa/TestPage.jsf/rationale

[fniessink]

Looks like this may be specific to the issue key (it has slashes). Solution may be to URL-encode issue keys. @dicksnel, which source type is this?