With Moodle 4.3 or later, with debugging enabled in Moodle, the warning Warning: Undefined array key "text" in .../mod/scheduler/mod_form.php on line 236 appears when adding a mod_scheduler instance to a course.

Environment: Moodle 4.3.5+ (Build: 20240712), PHP 8.1.19

Steps to reproduce issue

1. Enable debugging (Debug messages = DEVELOPER, Display debug messages = Yes)
2. Create a course.
3. Enable editing mode.
4. Click Add an activity or resource.
5. Select Scheduler.
6. Give it a name and click Save and display.

Expected results

The mod_scheduler instance is added with no errors.

Actual results

Error message: Warning: Undefined array key "text" in .../mod/scheduler/mod_form.php on line 236.