Shadow Lass and Mon-El have a brief discussion about Sensor Girl at the end of Legion of Super-Heroes (v3) #23. Mon-El mentions, from his perspective in the Phantom Zone, he wasn't quite sure how he perceived Sensor Girl and chalked it up to a fever dream. He obviously couldn't/didn't see her as Projectra or the mystery would have ended right there. So my question is: what do you think he saw? And just how powerful was Sensor Girl's illusions they scrambled senses across dimensions?
In-story, Projectra had a power boost before assuming the Sensor Girl identity (and then again afterwards) So interdimensional illusion-casting? Sure. Easily within her powerset.
“Times are bad. Children no longer obey their parents, and everyone is writing a book.” - Cicero
I actually always thought that he'd glimpsed her true identity as Projectra, but just thought that was unbelievable (because everyone knew Projectra had left our universe never to return!).