It seems that this effects both 2.2.2-stable and 2.4-stable

Create Custom Field¶

Set as both searchable and filter¶

Assign to tracker and project¶

This returns only the issues with Custom Field ID 1 and value
/issues.json?project_id=&cf_x=

This returns all issues
/issues.json?cf_x=

The Wiki from what I can see does not indicate that the project_id is required, but it seems to be. Not sure if that is intended or not, but needs to be fixed or documented as such.

Environment:
  Redmine version                          2.2.2.stable
  Ruby version                             1.9.2 (x86_64-linux)
  Rails version                            3.2.11
  Environment                              production
  Database adapter                         PostgreSQL

Not sure if it matters or not, but I have 2.2.2-stable and 2.4-stable both installed on Heroku and both have the same issue.