If users have certain events that meet specific conditions, their Timeline blocks in "All" and "Sort by dates" modes do not show some/any future events.

The conditions I found are:

• They have Workshop module(s) with a submission open date in the last 14 days and no submission close date.
• They have Questionnaire module(s) with an open date in the last 14 days. (Current Questionnaire works in Moodle 4.2.7 or lower)
• There may be more conditions...

Reproduction Steps:

1. Add a course starting yesterday and enroll a student who has no calendar events.
2. Add 6 assignments, A1 through A6, with different due dates from 01:00 to 06:00 tomorrow, respectively.
3. The student's Timeline block (All / Sort by dates) shows A1 through A5 plus a "Show more activities" button.
4. Add a workshop, W1, with a submission open date of 01:00 yesterday. Ensure the submission close date is not set.
5. The student's Timeline block shows A1 through A5, but the "Show more activities" button disappears.
6. Add another workshop, W2, with a submission open date of 02:00 yesterday.
7. The student's Timeline block shows only A1 through A4.
8. Add 4 other workshops, W3 through W6, with submission open dates from 03:00 to 06:00 yesterday, respectively.
9. The student's Timeline block shows NO events.