We have encountered a week that ends on the same day that the following week begins.I will try to explain it as best as possible:

We have a week that includes the dates from October 23 to October 29.
The following week begins again on October 29. 

If we have the course start date at 00:00 on September 25, it should not be possible for a week to end at 23:59 on October 29 and for the following week to begin again on October 29. This causes that week that begins again on October 29 to end on November 4 and not the 5 as it should be.

This is because on October 29 in our time zone we have a time change, at 3 on the 29th it will be 2 on the 29th.

This is the case in version 4.2.3 and I imagine that the latest weekly versions of 4.2 and 4.1 and 4.0 because we believe that the problem comes from MDL-75928

Steps to reproduce:

• Configure Moodle with a time zone that has a daylight saving time change (for example, Europe/Madrid).
• Configure a user with the same time zone.
• Create a course and set its start to October 23 at 00:00 hours.
• Create at least one more week.

Expected behavior: The first week will be from October 23 to October 29, and the following week should start on October 30 and end on November 5.
Current behavior: The first week be from October 23 to October 29, and the following week starts on October 29 and ends on November 4.