Checking tasks on newly created Software Project spaces are not working

Issue Summary

In Confluence, when creating a new space with the Software Project template, the tasks used as an example will be able to be checked and the following message is displayed:

Oops! Your task change couldn't be saved. There could be a few reasons for this.

Steps to Reproduce

1. Create a new space in Confluence (either through the dashboard, if not customized or through the Spaces directory from the sidebar)
2. Select the Software Project template and link it to a Jira project
3. Check one of the tasks used as an example

Expected Results

The tasks should be able to be checked and work as a demonstration for the user

Actual Results

The following is displayed:

Notes

Manually created tasks work on the same page. Even if putting it under the current existing task list.

Workaround

Manually create a new task, instead of using the default/example ones.