Remove timezone conversion of issue due dates for issue board cards

app/assets/javascripts/boards/components/issue_due_date.vue

@@ -53,7 +53,7 @@ export default {
       } else if (timeDifference === -1) {
         return __('Yesterday');
       } else if (timeDifference > 0 && timeDifference < 7) {
-        return dateFormat(issueDueDate, 'dddd', true);
+        return dateFormat(issueDueDate, 'dddd');
       }
 
       return standardDateFormat;

changelogs/unreleased/56251-fix-issue-board-weekday-shift.yml

+---
+title: "Fix weekday shift in issue board cards for UTC+X timezones by removing local timezone to UTC conversion"
+merge_request: 25512
+author: Elias Werberich
+type: fixed

spec/javascripts/boards/components/issue_due_date_spec.js

@@ -43,7 +43,7 @@ describe('Issue Due Date component', () => {
     date.setDate(date.getDate() + 5);
     vm = createComponent(date);
 
-    expect(vm.$el.querySelector('time').textContent.trim()).toEqual(dateFormat(date, 'dddd', true));
+    expect(vm.$el.querySelector('time').textContent.trim()).toEqual(dateFormat(date, 'dddd'));
   });
 
   it('should render month and day for other dates', () => {
@@ -53,7 +53,7 @@ describe('Issue Due Date component', () => {
     const isDueInCurrentYear = today.getFullYear() === date.getFullYear();
     const format = isDueInCurrentYear ? 'mmm d' : 'mmm d, yyyy';
 
-    expect(vm.$el.querySelector('time').textContent.trim()).toEqual(dateFormat(date, format, true));
+    expect(vm.$el.querySelector('time').textContent.trim()).toEqual(dateFormat(date, format));
   });
 
   it('should contain the correct `.text-danger` css class for overdue issue', () => {