When creating a schedule for the same job that consists of multiple simultaneous launches, only the first configuration entry will be executed, the rest skipped.

Example configuration, running every four hours on Saturdays and Sundays:

0 */4 * * 6-7 % environment=1
0 */4 * * 6-7 % environment=2
0 */4 * * 6-7 % environment=3

This results in only one started build for environment 1, and envs 2 and 3 are left without jobs.

Updating the configuration the following way offers a workaround:

0 */4 * * 6-7 % environment=1
5 */4 * * 6-7 % environment=2
10 */4 * * 6-7 % environment=3

But this should not be necessary.

The usage of H is avoided to have the jobs fit in their allocated time slots: all builds take about three and a half hours, so if H was used, a test scheduled for the 00:00-04:00 time window could start at 00:50 and so wouldn't fit in the allocated time window.