I don't think it's the Underbelly or lag. I have a pretty solid ~40ms ping.
It's picking up people the instant I click on a mage portal to Dal, and I can then target people from the list and they're all right there on the balcony with me. =\
There may be nothing you can do about it and that's fine. I just wanted to see if I was the only one with the issue. Cheers!