Steps to reproduce:
1) Download attached project 'ParticleTrailsisKinematicDisabled.zip' and open in Unity
2) Click on Play button
3) In Scene view, click on 2d view icon and focus on 'Sphere' game object
4) In Hierarchy window, chick on 'Sphere' game object
5) Disable isKinematic in Rigidbody component
6) Let Sphere fall for couple seconds
7) Press Pause button
------ Check Scene view, you will see distance between each trail is unstable(gif attached 'Trails5.5.gif')

Expected result: Distance between each trail of particle system should be stable (gif attached 'Trails5.4.gif')

Regression started from: 5.5.0a3

Reproduced with:
5.5.0a3, 5.5.1p1, 5.6.0b5

Not reproduced with:
5.3.7p2, 5.4.4p2, 5.5.0a2