To reproduce:

1. Download attached .zip file "ParticleTrails.zip" and open "ParticleTrail2017" project in Unity
2. Open "Main" scene
3. Click on Particle System gameObject in Hierarchy
4. Observe how Trails are rendering
5. Open "ParticleTrail2018" project in Unity
6. Open "Main" scene
7. Click on Particle System gameObject in Hierarchy
8. Observe how Trails are rendering

Expected result: On both "ParticleTrail2017" and "ParticleTrail2018" projects Trail rendering is the same
Actual result: On "ParticleTrail2017" and "ParticleTrail2018" projects Trail rendering differs

Notes:
- This issue reproduces on both Windows and OSX
- This issue appears only when you create Particle System on 2018.1.0f2 and newer
- "ParticleTrail2017" project still looks correctly on 2018.1, 2018.2 and 2018.3
- "ParticleTrail2018" project is broken on 2017.1, 2017.2, 2017.3, 2017.4, 2018.1, 2018.2 and 2018.3
- On both "ParticleTrail2017" and "ParticleTrail2018" projects Trail rendering was created the same way and with the same properties

Reproduced on Unity 2018.1.0f2, 2018.1.7f1, 2018.2.0b11 and 2018.3.0a3
Not reproduced on Unity 2017.4.6f1 and 2018.1.0f1
Regression on Unity 2018.1.0f2