Dev note for v1.8 or earlier:
For those of you experiencing sudden returns to the main menu, I've finally isolated the cause and resolved it.
The issue came from how certain quests were being scheduled, which could create a rare game-state desynchronization. When this happened, Ren'Py would quietly crash back to the main menu without showing an error. This also caused odd travel behavior on the world map.
Temporary workaround:
Use Skip Time until the next time period (“night”, “morning”, “afternoon”, “evening”).
Don't skip small increments of time and immediately travel after the quest updates, that’s when the desync could occur.
A permanent fix has been implemented and will be included in v1.9 (Early Access this weekend).
This update fully resolves the issue once and for all.
Hope it helps!
- Xera