(Case 1208775) Some prefab variant are broken after upgrade from Unity 2018.4 to 2019.3

Hello,

When we open our project with unity 2019.3.0f3 / 2019.3.0f4 some prefab variants are corrupted.
Some OnClick field in button components are empty after the import process.

This issue happens for all prefab variant from a particular prefab for no logical reason.

It's a show stopper for us to migrate our project cause this could maybe occured on any prefab variants (even if currently we didn't see the issue somewhere else)

Some precision that we saw :

- If we try to edit the field in 2019.3 and save the prefab, the field stay empty in Unity BUT if you check into the prefab file with any text editor, the value is changed in the file.

- If we try to generate a new variant based on the prefab that was problematic, the broken field from the other variants is working in this new one.

 

Ive had something similar but not just with 2019.3, whether it was 2018.x to 2018.x+1 or 2019.x to 2019.x+1 i have one prefab that keeps losing meshes, its simple to fix but there seems no blatent reason why they only lose that one

 

For us it's impossible to fix sadly

When we set the field by hand with the right value after saving the prefab, when we come back in the field value is gone for the editor (during play too the value is ignored)

 

@LeonhardP have you any idea on the ETA of this issue ? I know the QA reproduced it successfully but it will be probably only in the 2019.4 ?