IEF Simple Widget form is not saved when updating a block inside Layout Builder

Our QA team has identified an issue that happens when they try to update a previously saved block inside Layout Builder.

Steps to reproduce:

1. Modify the Basic block block type and add a text field:
- field name: field_text
- Label: Text
- type: plain text

2. Create a custom block and add an entity reference field pointing to the Basic block entity:
Block type name: Reference
- Field name: field_block
- Label: Block
- Type: Entity Reference
- Reference type: Basic block
- Reference method: Default

3. Set the Widget for the field_block as Inline Entity Form - Simple

4. Inside Layout Builder create a custom block of type Reference, fill the form and add the block.

5. Save the Layout. The error only occurs when editing previously saved Layouts.

6. Open the Layout again.

7. Configure the previously added block

8. Change the Text field (Basic block field) and Update

Current result: The text field stays unchanged.
Expected result: The Text field gets updated