Bug 1354068638 - Quest indicator shows up in City Square map

Noticed this a few times, but this time thought to actually capture it. Been chain-running T16 City Square maps, and occasionally on my minimap I'll get the quest indicator (yellow "!") on the barricaded door next to where you first portal in to the map. It only show up when you're some distance away from the portal, disappears when you get close enough (did not think to note what this threshold is) and of course there's nothing actually there as I finished the campaign ages ago and I literally have no quests to run at this point.

Image showing the quest indicator
...aaaaaand it's gone

edit: Had it show up again. Marker first popped up after I was circling back and entered the boss area, disappeared right as I got to the threshold of the area and did not return after I had left.

There
Gone
Still gone