This happens in every town, not just Teras. Not often, but it does happen. I walked through every room in Eye of V'Tull and there were no other instabilities, and the one here is a fire one, just like my attumement:


[Glaes Vein - 2244]
Tunnels veer off in three directions. Air currents have quickened, carrying the stink of sulfur and fire. To the south, the passageway widens, and a cavern is just visible around a bend of the walls. Opposite that, a tunnel to the north leads into deep shadow, in which no landmarks are visible other than a churned up pile of stone at its mouth to lend hazard to the darkness.
Obvious exits: north, south, northwest

>attune sense
You close your eyes, focusing on the background elemental flows.
You sense an unusual fluctuation emanating from the Eye of V'Tull.
Roundtime: 4 sec.

>stumble n
You begin to walk north but trip over something and end up stumbling your way there.

[Glaes Vein - 2247]
At the end of a severe twist of the corridor, the footing grows dangerously uncertain. Fraught with ankle-breaking crevices and canted at an almost impassable decline, the way would discourage the most sure-footed of beasts or dwarves. Within the walls to either side, the whisper of molten lava can be heard, rushing through its hidden course. You also see a point of elemental instability.
Obvious exits: south, down

>stumble down
You begin to walk down but trip over something and end up stumbling your way there.

[Glaes Vein - 2248]
At the foot of the precipice, the floor is a dangerous jumble of sharp glaes rocks. In the dense shadows, lumps can be seen here and there, the silhouettes giving away the fact that they are of softer origin than the formidable mountain. More common in the mess are the arched outline of rib-cages and jutting bones where the flesh of the tunnels' victims has yielded to time and heat.
Obvious exits: north, up

>attune sense
You close your eyes, focusing on the background elemental flows.
You sense an unusual fluctuation emanating from the Eye of V'Tull.
Roundtime: 4 sec.

~ Methais

Reading the wizard nerfs:
http://i.imgur.com/hNaDm98.gif

I didn't quite follow the issue (I've never seen it in RR), but as far as I understand, he's in the Eye of V'Tull LOCATION. In that case, the instability should show him the room it's in with a 116-type messaging. He states in the example it happens to be the only instability in that LOCATION, and it's his attunement.

I've definitely encountered multiple instabilities in the same LOCATION (because derp in RR Jungle I've gone in to the wrong one by mistake), and it generally operates as expected.

I would really suspect certain LOCATIONS are to blame. The "every town" may be true, though I haven't seen it myself ever.

Definitely sounds like something funky, but I have no clue at all.

Aha! And there we have it. Thanks, Coase