How to reproduce:

1. Locate the UnityYAMLMerge tool in “<Unity Editor version Path>\Editor\Data\Tools“ directory
2. Copy the path to the UnityYAMLMerge tool
3. Extract and open the “UnityYAMLMerge_BugReport.7z“ directory
4. Edit the “reproduce_merge.sh“ in Notepad
5. Change the value for “UNITY_YAML_MERGE“ with the path to the UnityYAMLMerge tool
6. Save the changes and run the script
7. Edit the “test_output/merged_output.prefab“ in Notepad
8. Observe the lines 41103 - 41114 in the Notepad

Actual results: The array is listed in this format: [ {}, {}, {} ]
Expected results: The array is listed in this format:
- {}
- {}
- {}

Reproducible in: 2023.1.0a1, 6000.0.65f1, 6000.3.3f1, 6000.4.0b3, 6000.5.0a4

Reproduced on: Windows 11 Pro (25H2), macOS 15.7.2 (reported against)
Not reproduced on: No other environment tested

Note: Both array interpretations are correct YAML-wise, however, Unity accepts only the expected (block/list) type array