- **app/finders/issuable_finder.rb:**

Adds note about how IssuableFinder is virtual.

- **app/finders/issuable_finder/params.rb:**

Ignore `release_tag` when searching on a group.

- **changelogs/unreleased/
  hide-inoperable-group-search-releases-filter-backend.yml**

Changelog.

- **ee/spec/finders/issues_finder_spec.rb:**
- **spec/finders/issues_finder_spec.rb:**

Adds test for filtering by group and release.

- **spec/support/shared_contexts/finders/
  issues_finder_shared_contexts.rb:**

Adds a release to the test suite.