We have time tracking data starting October 2017. I am unable to get time tracking data for anything before January 2018 in an Ad Hoc Report. It doesn't matter if a filter with a date before January 2018 is applied or not, no data before January 2018 gets pulled into the time tracking report. I am uncertain what setting can be changed to include the previous year's time tracking data, and I haven't been able to locate it looking through available support documentation.
Ensure that the fiscal periods are set to start on 1/1/2017, and change the number of periods to 36 (add 12 months essentially). Then, run the time slicing job, or allow it to complete on its normal schedule. Once the time slicing job has completed, run the Update Report Tables job WITH the calendar option to ensure that its updated correctly. Then, lastly, run the FULL load data warehouse job. After completion, the 2017 data should now show in the appropriate reports as expected.