How to reproduce:
1. Download attached project and open "Main" Scene
2. Select the GameObject named "GameObject" to display the SomeMonoBehaviour editor in the inspector (Notice how all fields are properly aligned)
3. Check the "Force Scrollbar" checkbox (the scrollbar should appear unless you have a ridiculously tall screen, in that case, try to make the scrollbar appear in the inspector window)
4. Notice how only the EditorGUILayout label field did not move and is now misaligned with the other methods

Expected result: EditorGUILayout.PrefixLabel should not give different results than EditorGUI.PrefixLabel and EditorGUILayout.Label
Actual result: When using EditorGUILayout.PrefixLabel, if the scrollbar is visible in the inspector, the subsequent field is not moved to the left to accommodate the change in width.

Reproduced with: 5.5.4p3, 5.6.3p3, 2017.1.1p1, 2017.2.0b11, 2017.3.0a7