I completed this way back in 8.1, but apparently a bunch of quests got reset at some point so I'm going through them again for rep. Anyway, I come to this one, and on the map it's pinned as nornal. However, after I complete the quest, the pin remains, and turns grey.

Now it's flagged up with two "bonus objectives" which have nothing to do with this one-off quest. For some reason these two Island Expedition bonus quests - Two-Socks Needs Help [52706 through 52713] and Valero Needs Help [52714 through 52721] - have been attached to it.

Here's a pic: https://imgur.com/a/nNnThYT