I have noticed that in this question on the right the time of the last activity is not shown. (Usually you have there 3 entries: asked, viewed - with number of views, active.)
When you view recently active questions in the given tag, the last activity is shown as Nov 9. (Which is when a bounty was placed on this question.)
Is this a bug? Or is this intentional?
I suppose that this can change when there is some new activity in the question. So here are two snapshots from Wayback Machine:
And also a screenshot: