I tried to create a timeseries chart in the report designer and found gaps in the time series. I struggled for a while with the gap threashold and trying to find what caused this.
As my database has null values for incomplete datasets I found that the charts then had gaps when trying to create a timeseries. This was resolved by setting the query to exclude null values when returning rows and used the clause: where columname IS NOT NULL
Attached is a screenshot, I thought I would just document this to help anyone else who came across this.