I wouldn't call it coincidence, I would call it a clear PR move to address hysteria that was blown up by the media.
I still fail to see how this was a "flaw"? Pointing out that the thinnest part of the phone's frame is where it will bend when more than 60 pounds of pressure are applied to it sounds more like common sense. It STILL is the weakest part of the frame on the 6s, but somehow it being made out of stronger aluminum so it takes more pressure to bend it there (which it will do) means it's no longer a flaw? That doesn't make any sense.
If I take a piece of steel and cut out a hole, then try to bend it, it will obviously bend where that hole is located. How does that make it a flaw though? Beams are riveted together on many bridges. If you were to overload the bridge with far more weight than it was designed to carry it would naturally break at those rivets, but does that make it a flaw when the use case (far more weight than designed for) far exceeds what the design was made to withstand?
What I'm saying is how can something be called a flaw when it is the weak point on a phone that isn't designed to be under those stresses in the first place? Should Apple start putting mini roll cages inside the phones in case someone decides they want to stand on their phone as well? After all, if someone intentionally (or otherwise) puts far more weight on a device than its ever supposed to withstand and it failed, that's a "flaw" right?