I am using the Zephyr plugin for Jenkins to report results. I cannot find any documentation on how it handles test cycles. Ideally I would like the results from a Jenkins pipeline reported in one cycle for a two week sprint and then have it automatically create a second cycle when the next sprint starts. When I select new cycle I get a new cycle on every execution even through my cycle is set to 7 days long. I have have not tried to pre-define a cycle and see what happens the next execution after the cycle end date.
The cycle duration option in Jenkins plugin determines start date and end date of cycle if you choose the option to create new cycle, nothing more. If you want all your executions to use same cycle then I suggest you created a cycle in Zephyr manually and select that cycle in Jenkins config.
The plugin doesn't have this behavior. You will have to manually change cycle after each period of time.
You might be able to simulate this behavior if you use pipeline script and calculate whether a new cycle should be created or old one should be used. I haven't tried this myself so you will need to check whether it' a viable solution.