As Unity is continuing to modularize the engine, they are moving some "core" classes like Input in separate assemblies called "Modules". This causes Bolt to stop finding the associated units in the latest preview versions of Unity.
We will try to hunt down and add the new modules by default in a patch version soon, but in the mean time, you can add UnityEngine.*Module to your Unit Options Wizard (under Tools/Bolt) if you notice units are missing.
For example, adding UnityEngine.LegacyInputModule now seems necessary for accessing the Input class:
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