This and the Clipper Chip aren't NOBUS. The NSA doesn't want you to know that the cryptosystem has law-enforcement access capability. The FBI doesn't care if you know as the kinds of criminals they are attacking don't do OPSEC.

NOBUS isn't just intentional vulnerabilities, it's any vulnerability assumed to only be exploitable by US IC, whether engineered or otherwise.

I think these qualify.

Well, the article mentions backdoor in Dual_EC_DRBG mostly targeting TLS/SSL communications, now we have Cloudflare, a much more scalable solution

Dual EC is sort of the archetypical NOBUS backdoor.