Steps to reproduce:

1. Download and import attached project.
2. Open scene: main.
3. Play.
4. Select GREEN particle system in Hierarchy.
5. Look at Limit velocity over lifetime.

Expected result: Positive or zero values.
Actual result: Negative values.

Notes: When Constant: Negative values is forbidden. But when it is Random between two constants, now it is possible to enter negative values. Also possible with curves.

Reproducible on: 5.4.0b2, 5.3.1p3, 5.2.4f1, 5.1.4f1.