Assignment submitted on due date/time marked as late

[ganymede]

Canvas Instructor Guide defines late submissions as:

"The due date is the date and time when the assignment is due. Student assignments submitted after the due date will be marked as late in the Gradebook. Due Dates are not required in Canvas, but they are helpful in managing course workflow and deadlines." 

However, I have submitted an assignment on the due date/time. Why was it marked as late?

[mzkm · Accepted solution]

11:59pm due date likely means 59min & 0sec.  

If you uploaded it even 1sec past, it could be marked as late.

Midnight due-dates are best to have, but I personally use 11:59pm as too many students confused 12:00am as being Noon.