Questionnaire with past open date causes malfunction in Timeline block

[HirotoKagotani]

We are using Questionnaire module 4.0.1 in Moodle 4.2.7.
Some of my students claim their Timeline blocks in "All" and "Sort by dates" mode do not show "All" future events.
I figured out that if students have one or more questionnaires with open dates in the past 14 days, their Timeline block do not show all future events.

Thank you and here is how to reproduce the problem:

Reproduction steps:

1. Add a course and enroll a student who has no calendar events.
2. Add 6 assignments A1 through A6 with different due dates 01:00 through 06:00 tomorrow respectively.
3. The student's Timeline block (All / Sort by dates) shows A1 through A5 plus "Show more activities" button.
4. Add a questionnaire Q1 with open date 01:00 yesterday.
5. The student's Timeline block shows A1 through A5, but "Show more activities" button disappears.
6. Add another questionnaire Q2 with open date 02:00 yesterday.
7. The student's Timeline block shows A1 through A4 only.
8. Add 4 other questionnaires Q3 through Q6 with open dates 03:00 through 06:00 yesterday respectively.
9. The student's Timeline block shows NO events. It says "No activities require action".

[mchurchward]

You reference a student's Timeline block. Is this a core block?