That article is equally vague as EMs allegations. Doesn't put forward any evindence. Doesn't even say Snowden said anything specific to sha-256. Yes: I believe the NSA has planted weaknesses into crypto implementations. No: I don't believe they managed to "infiltrate" sha-256. The algorithm is exactly defined, in contrast to a PRNG, which is only defined by it's features, not the algorithm. With the android RNG, yes, I think it's possible the NSA managed to plant predictability (it was taken from an apache project if I'm not mistaken).
I fail to see (that might be due to lack of imagination, of course) how sha-256 could be affected... there are no arbitrarily chosen magic numbers and the implementations are not obscure, it's the same algorithm in every implementation. I'm pretty sure a lot of people have been looking for shortcuts and I'm very sure noone has found any exploitable ones. The (relatively simple) algorithm has been implemented in CPUs, GPUs, FPGAs and ASICs in different ways and noone found a meaningful shortcut.
BTW: it would be really bad, but if a shortcut was found, we could stop the bitcoin network and switch.
This not going to happen just on ElectricMucus' belief with no evidence.