What to do when app and app_dev behave differently?

Question

symfony

The entity is written to the database incorrectly. The cache was cleared. On app_dev, the functionality works fine, on app, some lines seem to be ignored.
field in user:

fake:
            type: boolean
            default: false

I call the method in the controller:
$newUser->setFake(true);
as a result, everything works fine in app_dev and fake = 1 is written to the database,
and fake = 0 in app

Answer 1

put app.php in debug mode and debug why there false (0) comes to the database

Answer 2

Look at the difference in the config_dev.yml and config_prod.yml configurations
It would be better if they also gave an example of what does not work out in order to know which way to dig