Describe the issue. What is the expected and unexpected behavior?

Origin: #3258 (comment)

FlexModifiers and FlexItemModifiers contain wrong modifiers:

• align-self-flex-center
• align-self-flex-baseline
• align-self-flex-stretch
• justify-content-flex-space-between

Please provide the steps to reproduce. Feel free to link CodeSandbox or another tool.
Set in the breakpointModifiers any of these modifiers and see that in the classnames you see undefined.

You can see this here and here

Is this a bug or enhancement? If this issue is a bug, is this issue blocking you or is there a work-around?

This is a bug but not blocking.
If you're using JavaScript just use "justify-content-space-between", "align-self-center" and etc
If it is TypeScript explicitly specify the class through className and not through breakpointMods

What is your product and what release version are you targeting?