Have the criteria changed? I can't see any changes in Recent feature changes to Stack Exchange.
What is meta?
- Any Stack Exchange user can ask a question
- The community provides support, votes on ideas, and reports bugs
- Your voice helps shape the way Stack Exchange operates
Based on some comparisons between the September and December data dumps, it looks like was actually used on two questions, but you edited it out of the second one.
This question is the only other one that I can see that ever had ruby-2.0 on it, and although I can't guarantee that there wasn't another question posted with that tag between the two data dumps, I'm fairly certain that the system was behaving as expected in this case.