The Initial Modules appear to be clamped to a zero to 1 time frame since 4.8 was released. Projects that are converted from 4.7.6 will have correctly working particle systems, but adding a new particle system of the same makeup will force the new system to use a clamped range.
Left is created in 4.9.1, Right is created in 4.7.6 and project converted to 4.9.1
Attached 4.7.6, 4.8.3 and 4.9.1 project for clarity. 4.7.6 shows expected and working behavior, 4.8.3 and 4.9.3 show new particle systems not functioning but converted particle system still functioning.
RESULTS: Same as on left of picture above
EXPECTED: Same as right of picture above
**Quick Reproduction, open attached 483 or 491 projects**
Head over to the existing Questions & Answers thread and let us know what's up.