Extremely perceptive, Lucius.
You learned a bit about portals during your apprenticeship, and a bit more during your many travels. You know that an ancient network of them criss-crosses Faerun, mostly created by Netherese magi. They are a very old (and sometimes uncertain) means of travel.
This particular network consists of 16 portals connected to 16 other portals--a total of 32 magical connections (that actually conjoin locations rather than acting on a simple teleport function). You surmise that such a large network may have grown unstable over the years--this one could have been created as many as 1500 years ago.
Whether the network has been unstable the whole time, became unstable from overuse and will regain stability in time, or has simply stopped functioning correctly, is open for debate. Lucius, you'd guess that either of the latter two possibilities is more likely than the former.