These are labels and should be title case, unless they're part of the "non-grammatically-standard rules of not doing that in some cases" Mike mentioned, of course. If that's the case, this can be moved accordingly and marked as Not a Bug.
- Phrase: last_edited
- Current: Last edited
- Fix: Last Edited
- Phrase: last_edited_by_moderator
- Current: Last edited by a moderator
- Fix: Last Edited by a Moderator