Just posting this bug report in case other people look for it! It's a known issue with a simple fix:
When instantiating a prefab in Unity 2018.3, you might run into an issue where all its Bolt components are reset to their default state.
That means, for example:
- The source of machines is reset to Macro, and the macro reference is None
- The variables component is entirely blank
- A reference to this prefab elsewhere shows a null or missing
This happens for prefabs in projects that were created in the old prefab workflow (Unity 2018.2 and below) then opened in a newer version of Unity with the new prefab workflow (Unity 2018.3 and above).
The solution is simply to Reimport the affected prefabs. You can do so by selecting the prefabs, then choosing Assets > Reimport.
If you want to make sure you did not miss anything in your project, you can also use Assets > Reimport All. Note that a full reimport can be very long depending on the size of your project.
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