Sequelize Foreign key for "a" is missing on "a" while npm run build for next.js

[FoodHub9999]

I have a Next.js Project where i use Sequelize ORM for Database Model Definitions and so on. In Development everything works but when i try to build the project with npm run build i get this error:

Error: Foreign key for "a" is missing on "a"

What am i doing wrong and why does it work in development but not when building?

Here is a repo that includes my sequelize configs: https://github.com/FoodHub9999/sequelize