You're probably thinking of DES, which happened long before Dual EC (and long before many of the people working at RSA started their careers). But you can see that effect even today, for instance with NSA's "deprecation" of Suite B cryptography and the shade that cast over conventional elliptic curve cryptosystems.

I don't think one can reasonably defend adoption of Dual EC as somehow hedging a bet that NSA had found vulnerabilities in trivial block-based CSPRNGs, though. I think that decision was essentially indefensible, even at the time it was made; it's just more clearly batshit now than it was then.