Have you checked the migration directory?

• When you make changes to your data base and these changes are typically tracked in this directory. In these files look for the added default section or something similar to migrations.AlterField here you can check what the default value is. The script may be reading this migration file raising the error before the change to the proper default. I have ran into this issue previously, you can either manually change the values or delete the whole file and run it again.

Source: Previously had this issue.