1. The Vex arrived on Neptune shortly after the Ishtar Collective. 2. They retroactively inserted themselves into the history of Neptune, making it as though they always had a presence there. Chioma Esi states this is what happened on Venus as well. 3. The presence of the Veil stopped the Vex short of the habitat, preventing their temporal excursions. This seems to do with the Veil being "a window into the mind and memory of the universe" if it can prevent temporal alterations in its vicinity. 4. The Endless Night was not a one-off deal, as the Vex wove a simulation into Neptune's magnetic field to create a screen that isolates the habitat from the outside world. This explains why Neomuna was never found in any searches of Neptune.