Repro steps:
1. Open Bug scene from the following project:
https://drive.google.com/open?id=1Uid9A9JjtdXJqGWz_wN3VCjSsfUCN1xZ (project path is TestProjects\LWGraphicsTest)
2. Enter / exit play mode a few times (it may take 3-5 times to see the issue)
3. Observe console errors:

Assertion failed on expression: 'curveT >= GetRange().first && curveT <= GetRange().second'
UnityEngine.ParticleSystem:Simulate(Single, Boolean, Boolean, Boolean)
PlaySystems:OnEnable() (at Assets/PlaySystems.cs:19)

and

Assertion failed on expression: 'curveT >= m_Curve[lhs].time && curveT <= m_Curve[rhs].time'
UnityEngine.ParticleSystem:Simulate(Single, Boolean, Boolean, Boolean)
PlaySystems:OnEnable() (at Assets/PlaySystems.cs:19)

Notes:
- Inconsistent repro, takes a few tries
- The offending particle curve is the Szie over Lifetime curve on the GunBarrelEnd system. Removing any of its 4 keys fixes the issue.
- Issue introduced recently in the 2018.3 cycle