The commentor means Dual_EC, a random number generator. The backdoor was patented under the form of "escrow" here: https://patents.google.com/patent/US8396213B2/en?oq=USOO83.9... - replace "escrow" with "backdoor" everywhere in the text and what was done will fall out.

ML-KEM/ML-DSA were adapted into standards by NIST, but I don't think a single American was involved in the actual initial design.

There might be some weakness the NSA knows about that the rest of us don't, but the fact they're going ahead and recommending these be used for US government systems suggests they're fine with it. Unless they want to risk this vulnerability also being discovered by China/Russia and used to read large portions of USG internet traffic. In their position I would not be confident that if I was aware of a vulnerability it would remain secret, although I am not a US Citizen or even resident, and never have been.

Not op, but they probably meant https://en.wikipedia.org/wiki/Dual_EC_DRBG