Ah i think you have zeroed in on the source of the problem.

My calender settings in both models match the below.

So I have checked SYS01 has a Weeks Only line item - I think this is ok.

When I apply this as a time filter in the DAT03 module - I just get blanks——这就是我玩过滤器设置部件l I was able to match the requirement view rather than landing on the right solution.