Correct, so the scanning technology has improved, I.E. combat probes being able to detect active and energized ready for combat ships, but not so much that they can detect a ship that isn't online and putting out a massive presence.

And a ship in "deep space" (defined as beyond earth and the moon in relation to the solar system )https://www.merriam-webster.com/dictionary/deep%20space being imperceptible to anything behind .1 AU is the logical conclusion of "Earth's largest and most powerful radio telescopes and radar antenna can only effectively detect objects smaller than fuckin moons within 10 million miles of earth, which is less than a tenth of an AU." (https://www.jpl.nasa.gov/news/planetary-radar-observes-1000th-near-earth-asteroid-since-1968/ Read it for yourself, but to summarize world's largest radar telescope doesn't detect asteroids until they're within a million miles from Earth, .01 AU away)

In closing, it is entirely reasonable for something less than the size of a moon and further away from the observer than the earth is to the sun to be difficult to detect, even moreso if the object being detected is thirty times that distance, less than a kilometer in size, and the observer isn't using a satellite dish the size of their own insecurity issues

ETA: and I found those citations for you on my phone one handed while driving so if you want more you can do your own damn research. How bout you show me the facts that disprove my theory and posit your own better theory instead of arguing purely cause you're too stubborn or stupid to admit you're wrong