I took a few days to think about this before replying, and here's my take on the situation.
You may perhaps recall that about two weeks ago I advanced the theory that there is something strange afoot in the South Atlantic. That discussion ended when my assertion that there were oddities in the disappearance of the ARA San Juan was politely challenged. The San Juan is an incident like 911 or the death of JFK, in that there is nothing to be gained by debating it; we have all formed our own opinions by now, and nothing I can say will change anybody's mind.
I do believe that this new challenge by Chile is another piece in the puzzle, though what it means I cannot say. But I would note that the strength (if you can call it that) of Argentina's claim to the Falvinas, South Georgia, et al, rests upon the concept of the continental shelf. The UNCLOS is a very complicated subject, but if I wanted to undermine AR claims in the South Atlantic, I would start by chipping away at their claims to the continental shelf, and this old Beagle Channel dispute with Chile is all about that.
Another possible piece that came to my attention lately is the planned major upgrade to port facilities in the Falklands/Malvinas islands.
The upgrades started in Mare Harbor about five years ago
Now they have moved on to major upgrades in Port Stanley/Puerto Argentino. There's a map showing their relative positions
here.
Basically, Mare Harbor is the military harbor, and Port Stanley/Puerto Argentino handles civilian traffic.
Technically, this is a violation of a few UN resolutions, (UN GA 1514, et al), calling upon both parties to seek each other's permission before undertaking construction in the disputed areas, but "possession is 9/10ths of the law". Argentina is predictably upset about this. The governor of Tierra del Fuego has fulminated about how it will take business away from Ushuaia, though I can't see how that makes any sense at all.
The big loser I see here is actually the port of Montevideo. I talked before about the huge flotilla of fishing boats that stays at Mile 201, just outside Argentina's EEZ, and fishes illegally inside that EEZ by turning off their transponders. The Chinese are the biggest offenders by number, but the Spanish boats spend the most time with their transponders off, in direct violation of EU rules stating that all fishing boats must have their transponders on at all times. At the moment, these boats go to the port of Montevideo for supplies and repairs. But if they can get what they need at a new upgraded port in the Falvinas, that will be a hell of a lot closer to their (illegal) fishing activities.
Of course all of this may just be random crap happening, and a desire on the part of the UK to have a base for exploiting Antarctic resources, and pursuing old territorial claims there, as the polar ice cap melts. But the UK garrison in the Falvinas does seem suspiciously large given the absolutely brutal reductions inflicted upon the UK military in recent years. Especially given that the Argentine navy is but a pale shadow of its former strength.
To my nasty, suspicious mind, it does seem like an odd concatenation of circumstances, but only time will tell.