Steps to reproduce:
1. Log in as admin (or any other user with dashboard)
2. Go to 'My dashboard'
3. Add 'Products with the lowest stock' block
4. In 'Stock' field add a value of 100
5. 'Save and close'

Actual result:
Error 500 occurs (see pic). In this env due to test-fixtures there are products with infinite stock or stock in range 100-104. When 99 is selected there is no error; error occurs after 100+ stock. Problem occurs due to products_with_lowest_stock.html.twig reading the 'Category' field (ibx-7165_2.png).

Expected result:
User is able to set any stock value (or at least validation error message occurs)