SUMMARY When completing an instance of a recurring task in Kontact, Kontact updates the task's due date to the next date according to the task's recurrence settings. This status however does not sync to NextCloud, i. e. the task in NextCloud remains unchanged. When completing the task on an Android phone in the Tasks app (https://tasks.org/), the app creates a new occurence according to the task's recurrence settings. The task syncs correctly to Thunderbird Lightning, but in Kontact the start and due dates of the task are off by several days. After restarting Kontact, the task's due date corresponds to the task's settings, but is displayed incorrectly in the task list (actual due date is shown in start date column, due date column shows date two days after start date). STEPS TO REPRODUCE 1. Create a new to do item in Kontact on a NextCloud calendar with the start date set to current date/time (filled automatically) and the due date set to some time in the future. Set the recurrence to Daily / every 1 day / never ends. 2. Wait for the task to sync to NextCloud and validate the task's settings on another device, e. g. an Android phone. 3. In the list of to do items in Kontact, click the checkbox of the item that you just created to mark this instance as complete. 4. Wait for the task to sync (as described above, this might never happen). 5. Mark the task as completed on another device, e. g. an Android phone, and wait for the task to sync. 6. Check/validate the updated task's settings in Thunderbird Lightning and Kontact. OBSERVED RESULT The start and due dates of the completed task gets incremented in Kontact as per the task's recurrence settings. However, the task in NextCloud does not get updated accordingly, i. e. it retains its uncompleted status and original start and due dates. When marking the task as completed on the other device (Android), the updated task syncs correctly to NextCloud and has the correct updated due date in Thunderbird Lightning. In Kontact, however, the task shows seemingly random start and due dates several days in the future. After restarting Kontact, the task has the correct new due date, but shows an incorrect due date in the task list (actual due date is shown in start date column, due date column shows start date + 2 days). EXPECTED RESULT After completing the task, the corresponding task in NextCloud should reflect the new start and due dates. Completing the task on any device should result in the task having the new due date set according to its recurrence settings. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Kubuntu 19.10 (available in About System) KDE Plasma Version: 5.16.5 KDE Frameworks Version: 5.62.0 Qt Version: 5.12.4 ADDITIONAL INFORMATION