I am upgrading my db from Odoo 13 to Odoo 17. I created a new staging db from the production, then removed all custom modules (uninstalled them), then I went to the upgrade section and started the upgrade. 

The upgrade has stopped at a specific field which is found in a customized module in Odoo 13 I already uninstalled and conflicted with a field with the same name in Odoo 17.

Why did this happen? Even though I uninstalled the modules. It shouldn't make a conflict