Breeding May Still Be Broken?

I don’t know alot about how breeding works, but to my knowledge, you can only gain your level X2 in GS.

I’m level 240, and my GS 200ish creature jumped up from 200 to 1100, I bred it with a GS 0.

If it matters, the GS 200 was a Lord Zankai and the other was a Vicious Wolpertinger, I believe.