When a User calls the LoadAssembly method on Unity 2017.4.6f1 or newer, it loads the first assembly, but when a User loads the second one it gives him the ref on the first assembly, it's like if it was ignoring the given path/assembly. In the sample project, a User is printing the assembly version, to see what of them was just loaded

To reproduce:

1. Download attached project "missscript.zip" and open in Unity 2017.4.5f1
2. Open "Scene1" scene
3. Enter Play mode
4. Note that in frame 10 it will load the first assembly, you will see the library info on console's output: "Load library 1 at frame 10:Lib4, Version=1.0.6801.32800, Culture=neutral, PublicKeyToken=null".
5. Note that in frame 60 it will load the second assembly, you will see the library info on console's output too: "Load library 2 at frame 60:Lib4, Version=1.0.6801.32894, Culture=neutral, PublicKeyToken=null".
6. Open project "missscript.zip" in Unity 2017.4.6f1 or newer
7. Open "Scene1" scene
8. Enter Play mode
9. Note that in frame 10 it will load the first assembly, you will see the library info on console's output: "Load library 1 at frame 10:Lib4, Version=1.0.6801.32800, Culture=neutral, PublicKeyToken=null" (This is expected).
10. Note that in frame 60 it will load the second assembly, the output in this case should be:: "Load library 2 at frame 60:Lib4, Version=1.0.6801.32894, Culture=neutral, PublicKeyToken=null", but it is loading the first assembly again: "Load library 2 at frame 60:Lib4, Version=1.0.6801.32800, Culture=neutral, PublicKeyToken=null".

Notes:
- This issue appears on both Windows and OSX

Reproduced on Unity 2017.4.6f1, 2017.4.9f1, 2018.1.9f1, 2018.2.5f1 and 2018.3.0a9
Not reproduced on Unity 2017.4.5f1
Regression on Unity 2017.4.6f1