I see. Well, I suspect that the ability to sort "A-Z" should produce the same results as the ability to sort "Smallest to Largest" in that both refer to the same concept if these were actually numbers, and not just a set of digits.
However, the problem seems to be that the underlying DataType in the field called Open is NOT numbers, but text, perhaps Short Text.
Note that the values in Open are left aligned (the way text is aligned) whereas the values in Closed are right aligned (the way numbers are aligned).
That suggests to me that "somehow", the datatype was changed from a number datatype (integer, long integer, etc.) to a string or text datatype.
I can only guess that when you "added a row" that also involved the datatype change in some way. Change it back to the appropriate number datatype and you should be good to go.
By the way, because of issues like this, I tend to use the term "digits" not "numbers" in describing the actual values because a text string can consist entirely of digits which are not numeric in the same sense that actual numbers are. For example, you cannot add two phone numbers together and come up with a meaningful result (555-232-5555 + 666-323-5555 makes no sense at all). Of course, you can add 10 dollars and 20 dollars and come up with 30 dollars because THOSE digits are in fact numbers. Does that make sense?