Reproduction steps:

1. Open "UnityEventMultipleComponent.zip" project
2. In the Hierarchy window click on "Fixed"
3. In the Inspector window click on "Invoker (Script)" cog image in the right -> "Execute"
4. See the output in the Console window:
"First - 1
Second - 2"
5. In the Hierarchy window click on "Broken" **Fix this first
6. In the Inspector window click on "Invoker (Script)" cog image in the right -> "Execute"
7. See the output in the Console window:
"First - 1
First - 2"

Expected Result: The "Broken" prefab should output like the "Fixed" prefab
Actual Result: The "Broken" prefab outputs the same prefix both times

Reproduced with: 2018.1.0a7, 2017.3.0f2, 2017.2.1f1, 2017.1.2p4, 5.6.4p4

Note:
** To fix the "Broken" prefab for the repro steps to work, you have to drag "Debug Action String Component" in the second slot of the "Invoker" script -> "No Function" -> "Debug Action String Component -> Execute". (Shown in video)