Magento 2.3 After changing product all categories are unassigned

Question

I have a problem with Magento 2.3.3. We have a lot of normal products and also use Group and Bundle products. All products are assign to a category (or multiply categories) and also displayed in frontend.

Our Issue:

1. After changing a normal product, like the quantity, the product is no longer assigned to the category/categories and will not displayed in frontend.
2. After looking in the category, this SKU is no longer assigned and we have to assign it again.
3. After that, the product displayed again and all is fine.

We have to do it with every product change... Is this issue already known? Did someone have the same issue and fixed it?

Hopeful that someone can help.

Thank you.

Answer 1

I could solve this issue by myself.

It was caused after Data-Migration. We have to update Attribut-Sets with "Category IDs" to solve it.

For all with the same Problem: In backend go to Stores-> Attributes -> attribute set

From there select the first attribute and go editing. Now you can see on the right block "unassigned Attributes". Search and assign "category_ids". After that make that changes on every Attribut-Set.

If all changes are done make sure that you flush and clean cache! Now all products can be edited without loosing category assignment.

Hope someone helps my solution!