When using multiple groups with nested attributes the index in data-bs-target is assigned based on first group and not the group the collapse is in.

Steps:

1. Add custom block to configuration using nested attributes with more than one group.
2. Create Landing page.
3. Add this block.
4. Open block settings.
5. Add a few new instances of the first group.
6. Add a new instance of the second group.
7. Using inspect check the value of data-bs-target for the new instance of the second group.

Actual result: The index at the end in .block_configuration_attributes_group2_value_attributes_6 is based on the last instance from the first group.
Expected result: Indexes are created separately per group.

Remarks: In effect it's possible to create duplicated class with the same number.

Things to check during retest:

• which group instance is collapsed
• what is deleted when using bulk delete