It's not hard to guess why in g1 transformers marvel comics Goldbug turned back into Bumblebee. Goldbug toy probably wasn't selling as good as Bumblebee toy so they returned to older version of the character, thats my guess. But it's still nice to try to find some explanation in-universe. So, that's what we get in-universe, thats what Ratchet says to Bumblebee about that, after rebuilding him as a pretender and making him more powerful too:
It may be connected with how limited Ratchet's influence in constructing Goldbug was, as he arrived when humans did a lot already and after that he had to work with them. He might just want to reverse what humans did and he considered unfitting. But I also like to think what Ratchet ment by rebuilding him this way is that Bee can be powerful without changing who he is, that he can be strong as himself, be stronger while still being Bumblebee :)