It always says "Just now" or "X minutes ago" or "X hours ago", etc., but now it said the exact time of when the post happened, which never happened before...
I think its weird when it does that, it happened to me a couple of times today, but it does no harm and if its a glitch it will probably be fixed sooner or later.
I haven't seen that one before. But I do know that the developer is working on various time issues within the community. So hopefully it will all work smoothly soon.