When I was working on my first Django project, I encountered a problem where modifications done inside pre_save signal were not stored in the database. Back then it took me a couple of hours to figure out what is wrong and how to fix it. I’m sharing what I’ve learned to save that time someone else.
https://mirekdlugosz.com/blog/2025/django-data-modified-in-pre-save-signal-is-not-saved/