I'm an Architect and I have worked on large projects in London, although not this one thankfully[0], so I thought people might like to know how the process of designing a building like this works.

A developer hires an international 'starchitect' like Viñoly to design them an office block because the architects reputation for design helps them to get away with a larger building on the site and therefore get more net lettable area for their investment in land.

I don't know anyone who works for Vinoly, I've no idea what it's like to work for him, but I know other people who have worked in similar 'gesture architecture' practices and this is how it usually plays out:

The big boss will do a nice sketch of how he thinks a walkie talkie shaped skyscraper (or whatever shape is in fashion in the office) will fit on the site and then hand it off to a more junior member of staff to solve all the real problems. Meanwhile, he will have to go back to the international lecture/meet/greet circuit that pulls in the jobs and maintains their reputation for world class architecture.

The project team will then usually have a very tight deadline to produce the initial design, probably mostly drawn up by a team of recent architecture graduates who would be pretty low paid[1], and who will almost always end up working very long hours and weekends unpaid overtime to meet the deadline. Where the lead architectural practice is not based in the UK there will also be a local architect who will advise on local regulations, prepare the submissions for planning permission and generally deal with other regulatory authorities.

There will also be a large consultant team on a project of this scale. Probably consisting of two teams of civil engineers; one for superstructure and one for substructure. A geotechnical expert for the foundation design. A whole spread of HVAC engineers, probably separate mechanical, electrical, drainage and ventilation specialists. A facade engineer who specialises in problems specifically to do with the design of the glass cladding system. A fire engineer to design the fire escape strategy and help negotiate the fire fighting strategy with the local fire brigade. A vertical circulation engineer to design the lift and escalator strategy. A bomb blast engineer to model the effects of various bomb attack scenarios on the cladding and structure. A security consultant to advise on how defendable the building is and to design the cctv, active tramp deterrent systems :-( etc. Finally a quantity surveyor will advise on how much this will all cost.

All of these people will have been consulted briefly, probably mostly by video conference, across a couple of time zones, before the planning permission submission[2]. All their requirements have to be juggled between the different disciplines by the architect. As an architect who has done services coordination on skyscrapers and international airports, I can tell you it's not easy. One of the most frustrating things is that engineers from different disciplines don't talk to each other, even if they are working for the same firm. On top of this, the time allowed to prepare the planning submission will be a few months at most, and a lot of the effort will be spent on optimising the design and more importantly the presentation strategy to get through the planning permission process.

Once the planning permission submission has been approved, the overall shape of the scheme is fixed and hence the parabola shape can no longer be designed out. Therefore, if no-one notices a problem like this until after the planning submission, or perhaps fails to get someone higher up to take it seriously enough to change the concept design, then they will have to remedy it by using special anti glare coatings or just plain hoping it wont be too bad. This is for a couple of reasons: because the developer will be exerting large pressure to speed up construction as they will be paying a large amount of interest on the loan for the cost of the land, because consultancy fees to redo the design would be in the order of millions at this point and because getting planning permission for a scheme like this is very politically controversial so you don't risk doing it twice if you can avoid it.

So, you can probably see how something like this could easily have happened.

[0] Because it's pug ugly, not because of the solar death ray thing, that's quite amusing really.
[1] Something like £20k per year in London, which is a crap salary after 6 years in University.
[2] In the UK this is a semi-democratic consultation process which occurs at local government level and involves publicly presenting the designs to local councillors to give residents of the area a chance to raise a formal objection.