Are you using a filter action? If so, edit the filter action and set it up so that it filters only on the specific fields you wish to filter on. By default, it will filter on all fields, which may be causing the problem.
Doing action from trend to map. The map values are going null because of date field is missing in the view.
Add the date field in detail or tooltip in marks card else column or rows shelf(Uncheck the “show header” option)
Let me know if this helps.