Repro steps:
1. Create a new particle system
2. Move or rotate the particle system in the scene view
3. Press Ctrl + Z to undo
4. Error message appears:

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.CollisionModuleUI.SyncVisualization () (at C:/buildslave/unity/build/Editor/Mono/ParticleSystemEditor/ParticleSystemModules/CollisionModuleUI.cs:290)
UnityEditor.CollisionModuleUI.UndoRedoPerformed () (at C:/buildslave/unity/build/Editor/Mono/ParticleSystemEditor/ParticleSystemModules/CollisionModuleUI.cs:160)
UnityEditor.ParticleEffectUI.UndoRedoPerformed () (at C:/buildslave/unity/build/Editor/Mono/ParticleSystemEditor/ParticleEffectUI.cs:267)
UnityEditor.ParticleSystemInspector.UndoRedoPerformed () (at C:/buildslave/unity/build/Editor/Mono/ParticleSystemEditor/ParticleSystemEditor.cs:80)
UnityEditor.Undo.Internal_CallUndoRedoPerformed () (at C:/buildslave/unity/build/artifacts/generated/common/editor/UndoBindings.gen.cs:199)

Notes:
- Regression, introduced between 23st of Feb and 1st of March.