To reproduce:

1. Download attached "FBX_serialization.zip project and open in Unity
2. Open the Assets > asset.fbx file in a Text Editor - You should see that it's a Kaydara FBX Binary
3. Click on the asset.fbx file in the Project window - Tou will get Error in Console saying that Unity failed to import the FBX
4. Open the Assets > asset.fbx file in a Text Editor - You should see that it's now a YAML file

Notes:
- This issue happens on both Windows and macOS
- A .FBX file corrupts when the Inspector rounds the Transform values in OnInspectorGUI and calls ApplyModifiedProperties

Reproduced on Unity 2018.3.14f1, 2018.4.4f1 and 2019.1.0f1
Not reproduced on Unity 2017.4.30f1, 2018.1.9f2, 2018.2.21f1, 2019.1.0f2, 2019.1.11f1, 2019.2.0b10 and 2019.3.0a10