Higher Realms
One of the Elders of the Dragon Race, a guy called Qyzzei, also happens to be a Divine Stars Formations Master. When he went into the Wisp Main World, he had the responsibility of looking inside Anti-Divine Sense protection formations.
Qyzzei was only able to do such a thing thanks to a Secret Technique that he himself developed. Also, it wasn't something easy to do and had a big backlash in the user's Soul. If not because of the issue about the Dracophoenix, he would never use it that lightly. The higher the level of the Formation, the worse the backlash.
The Anti-Divine Sense Protection Formation in Cinty's house was obviously a high-level one. Otherwise, she wouldn't have stayed in the Wisp Main World to start with. Qyzzei did not even appear in this meeting since he had to recover immediately after. It could be said that he did an excellent job hiding his injury while he was in the Wisp Main World.