Hello, i bought the Huge ship conversion kit, and there is an imperial Gozanti quickbuild that installs it a dorsal turret.

In the points lists, there is no turret allowed on the imperial gozanti

is there an errata somewhere?

Nope. Often Quick Builds will break standard squad building rules. For example, Fang Fighters lack any modification slots, but Fenn Rau Quick Build has Afterburners equipped. So I wouldn't expect the Gozanti to get a turret slot any time soon.

Quick Builds have always allowed "illegal builds". I saw a CIS Wing card that allowed Grevious to be a Wing Leader for a bunch of Vultures. Besides the fact that they are fast to put together, I might want to try them out at some point.

That's why I love quick builds! More options that would normally be unavailable. I just wish we had more quick builds for wings and huge ships!