Not able to add to List field with 0 as the first machine name.

Problem/Motivation

I have a List (text) field that I ended up, for migration reasons, using the number 0 as the machine name of the first Allowed value. Migration went great. Now, months later, I need to add another item to the list. So I went to add it and got a "Value field is required." message under the Value field of the 1st Allowed Values enter (See Pics in files)

Steps to reproduce

I tried it in https://simplytest.me/ and got the same problem.

1. Used Article Content type
2. Add List (Text) Field
3. Enter Name of first Value
4. change machine name to "0" (number 0)
5. Enter Name of 2nd Value
6. Enter Machine Name of 2nd to "1"
7. Save settings
8. Created test article
9. Enter values for that field
10. Go back to add 3rd Value to Content type's field

It won't let you! You get an Error message "Value field is required."

I have a lot of these already done and migrated. If we need to add values down the road, what do we do?