The only way I've been able to progress past the Julia event is to swap bodies while not having saved Ashley fully. Immediately after the swap (while still Julia), go back to your house. You then just have to do absolutely nothing in the library waiting for 5 or 6 scenes until you get swapped back and chaotic events happen (While you can try to leave, the game will not let you and my best guess is that the timer to the next scene resets). You can then go to floor 24, get a scene and continue to floor 25.
I did try this same scenario after fully saving Ashley and doing all Julia dates, but the scene plays a bit differently and I couldn't get it to progress. I also want to mention that I didn't actually complete the heroic ending because near the end I talked to Val at school and there was a choice option that softlocked the game and my save was right before the Julia event and I haven't played it back yet.
Potential other requirements to progress past Julia event this way: My lowest floor was 12. No one was charmed; I was Rosa (lvl 21), My teammates were Val (lvl14 + dating), Sarah(lvl14 + doll + House scene), Cassandra (lvl14 + all Sarah scenes and went on date), Molly (lvl 14 + quit job through persuasion after 3rd date), Ashley (lvl 8 + Jane helped clear mind but haven't done contract scene). Kate was in the plaza (I was waiting to tell her that Brittany was an alien), Brittany hadn't been met yet, and I had done the first two monster capture quests and went on a date with Erin, unlocking the monster ranch scenes for naga and mature slime.