Nope, not at the request of Robert Beltran at all. He hated the whole idea of throwing them together in the finale. Kate Mulgrew is on record (at cons) as saying that she came up with the stunning idea that "Sexy went with sexy". I have my own personal theory about Mulgrew's self-serving agenda there, but that's another subject
Certainly, before "Human Error" Beltran joked with Jeri Ryan that her then boyfriend Brannon Braga would never write a C/7 thing and Jeri told him that she was going to tell Braga that - she did and Braga came up with "Human Error" which isn't even really Chakotay/Seven, it's Seven/hologram.
That was supposed to be the end of the joke, but then Braga left to work on "Enterprise" and Ken Biller took over as Exec Producer. When "Endgame" rolled around, it was wall-to-wall Janeway x 2, so scrabbling around for something for Chakotay and Seven to do in the episode, Biller maybe went KM's suggestion on C/7. Braga is on record as saying he told Biller NOT to do C/7, but Biller ignored him.
So Beltran and Ryan had a joke about C/7, but desperate for ideas, Biller made "Human Error" something it wasn't in "Endgame". That's my take on it from various cons and interviews etc.
I still can't watch "Endgame" because of the C/7 (I'm a J/Cer), but now all these years later, I think it did more good than harm as all the J/C, J/7, D/7, C/P fan fic writers wrote stories to fix "Endgame" and gave a real boost to several 'shipper communities which are still on a high now in most of them
