Random shift lengths when using time-restricted rotations

Issue Summary

This is reproducible on Data Center: YES

Steps to Reproduce

1. Build a rotation that alternates at least 2 users, uses a custom shift length, and is restricted to time intervals

Expected Results

The shifts would remain consistent in duration

Actual Results

Due to the time gaps between shifts that should not be counted the shift lengths vary, at what appears to the user, to be random intervals. Ideally, the time restrictions would be accounted for before the schedule is built to avoid this issue. 

Workaround

The workaround would be to use multiple rotations.