Issue Summary

Dashcard date filters (such as "due this month", "due this week", "today") can return incorrect results

Steps to Reproduce

1. Create a Dashcard that was set up when the user's account defaulted to America/New_York timezone
2. Ensure your browser/system timezone is set to a significantly different timezone (e.g., Japan/Tokyo which is GMT+10, 14 hours ahead of Eastern Time)
3. Create a Trello card with a due date of October 1st at 9:00 AM in your local timezone (Japan)
4. On September 30th (in your local timezone), filter the Dashcard for "cards due this month" (September)
5. On October 1st morning (in your local timezone), filter the Dashcard for "cards due this month" (October)

Expected Results

September 30th in Japan:

• Only cards with due dates before midnight September 30th Japan time should appear
• Card due October 1st 9:00 AM Japan time should NOT appear in September filter

October 1st morning in Japan:

• Dashcard "due this month" filter should show October cards
• Card due October 1st 9:00 AM should appear in results

Actual Results

September 30th in Japan:

• Card due October 1st 9:00 AM (Japan time) incorrectly appears in September results
• This occurs because the system evaluates the due date as September 30th 7:00 PM Eastern Time

October 1st morning in Japan:

• Dashcard still shows September data
• "Due this month" filter doesn't switch to October until it becomes October in Eastern Time (14 hours later)
• User cannot see their October cards until late evening Japan time

Additional symptoms:

• "Due this week" filters show cards from the wrong week
• "Today" filters may show yesterday's or tomorrow's cards
• The timezone offset causes multi-day discrepancies for users far from Eastern Time

Workaround

No recommended workaround at the moment