Okay, so in The Dark Secret, it's stated that the dreamvisitors were created by a SandWing. But in the Jade Winglet arc, we find out that they were made by Darkstalker. So what gives? Well, remember how apparently SandWings stole most of the NightWing treasure? They took one of the dreamvisitors. That led to a bit of a mix-up. Some slightly older scrolls said that they were made by a SandWing because there was one in the SandWing treasury. But scrolls written by the NightWings fixed that and it became more common knowledge that they were made by a NightWing. But since the dragonets' scrolls were often outdated, Starflight never got that information. 

Ah kay, see yall

PS I know this is just something Tui forgot, but this my interpretation of the in-world explanation. Hehe, that kinda rhymes...