From your first link:
I misspoke when I wrote that NIST made “internal changes” to the algorithm. That was sloppy of me. The Keccak permutation remains unchanged. What NIST proposed was reducing the hash function’s capacity in the name of performance. One of Keccak’s nice features is that it’s highly tunable.
I do not believe that the NIST changes were suggested by the NSA. Nor do I believe that the changes make the algorithm easier to break by the NSA. I believe NIST made the changes in good faith, and the result is a better security/performance trade-off.