Scoping rules for undefined type guard in Typescript

I've been playing with the code in question Unexpected "never" in Typescript

I am trying to understand the undefined guard, and assumed that the variable is inferred to be not null / undefined in the scope of entire block following the check.

interface IProperties {
    foo?: {
        aaa: string
        bbb: string
    }
}

function init(properties: IProperties) {
    if (properties.foo) {
        type FooOK = typeof properties.foo;  
        for (const x of [1, 2, 3]) {
          type FooOrUndefined = typeof properties.foo;
        }
    } 
}

The types are inferred as follows:

type FooOK = { aaa: string; bbb: string;}
type FooOrUndefined = { aaa: string; bbb: string;} | undefined

Could anyone explain why the type in the loop does not take the guard into account?

Playground link