Mining node display bug?

I needed some tin so I flew out to the Ghostlands and found a node. I have a lot of reading to do for my business, so after I mined the node I waited patiently while getting some reading done, glancing over every minute or so to keep an eye out for the respawn. About 15 minutes later I still did not see the node respawn, but I watched as another player rode up to me, dismounted, mined the thin air in front of me, mounted up, and rode off.

Clearly the node had respawned, but did not show up on my screen as I was looking. Is this an intended function, perhaps to prevent bots from camping a node, or is this a bug?

Dunno about Ghostlands but server often has a delay in Northrend when loading sub-zones, so I think that is what you have experienced.