Blueprint Independent Rig Modules fail to keep changes to public variables inside of Modular Rigs after closing and reopening the editor

The problem is that when adding modules in modular control rig, I can not change values for module variables - as soon as I close and reload the Unreal Editor, values snap back to default values.

I created new module and modular rig and by default it seemed to be working fine. Then I copied over some variables from my own module, added some nodes and the bug started happening also in the new test modular rig. I removed everything I did trying to find the culprit, but the modular rig stayed broken even with just single float variable.

In 5.7 it worked fine.

WORKAROUND: The issue can be temporarily resolved by loading the Rig Module into memory before opening up the Modular Rig. Opening the Rig Module or right-clicking it in the Content Browser should do this.

Steps to Reproduce

1. Create an new rig module in 5.8
2. Add a variable, make it instance editable.
3. Compile and save
4. Add new module to new modular rig.
5. Modify new variable
6. Compile and Save
7. Restart editor and open modular rig.