Task due on Sunday does not appear on Sunday

Steps to reproduce

1. Create a task in the tasks app, change the due date to Sunday, and make sure "All Day" is checked.
2. Change the calendar to week view, and go to the week where the task is due.
3. You will notice that the task is not present on Sunday.

Expected behaviour

The task appears right below the "Sunday" header in week and day view.

Actual behaviour

The task will only appear in the month view or task view. It will not appear in the week or day view. Note: The calendar will briefly show the task when in week view right before the page is fully loaded, but right after the page and all other calendars are loaded, the Sunday tasks will disappear.

Calendar app

Calendar app version: 2.2.0

CalDAV-clients used: iOS CalDAV integration

Client configuration

Browser: Firefox 87 (also present in chromium based browsers like Edge)

Operating system: Windows 10

Server configuration

Operating system: Ubuntu 18.04

Web server: Apache

Database: MariaDB

PHP version: 7.4

Nextcloud Version: 20.0.8

Start by reproducing the missing all-day Sunday task in the calendar's week and day views, comparing it with month and task views. Trace the task rendering and date-range handling used after the page finishes loading; done means the task appears below the Sunday header in both views without disappearing.