Working Days - End Date not matching what is set in Calendar

Noticed something with our Working Days Calendar. When I go to Administration > Working Days I can see my two calendars. Something I noticed is the end date of my calendars shows 12/30 instead of 12/31. When I click on the calendar I can see that 12/31 is marked as a working day.

Has anyone else run into this? I also noticed my other calendar has end date of 09/29/2020 but the calendar shows 09/30/2020 as a working day. Not sure why it doesn’t list the end date as the actual last date indicated in the calendar.

I just need to be sure the working days is in fact including 12/31/2020 and 09/31/2020 in my calendars.