forceSelection not clearing invalid single numbers/strings

[gustavomerini]

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Plunkr Case (Bug Reports)
Please demonstrate your case at stackblitz by using the issue template below. Issues without a test case have much less possibility to be reviewd in detail and assisted.

https://stackblitz.com/edit/github-9pxw5z?file=src/app/app.component.ts

Current behavior

If I type a number/single string that would not bring any valid value on an Autocomplete(forceSelection=true), it does not clear the invalid value.
If I type a number with a letter, it does clear (this should also happen with the single string/number) and after that it does also clear the single number (as shown on the example bellow), but on the first time I type the number, it does not clear.

Expected behavior

It should clear the invalid value just like it does after typing a number plus another character.

Minimal reproduction of the problem with instructions
type a number on a p-autocomplete (forceSelection=true), for exemple "1" then press tab, it should clear the value because it is an invalid value.
https://stackblitz.com/edit/github-9pxw5z?file=src/app/app.component.ts

• Angular version: 7.0.0

• PrimeNG version: 7.1.2

• Browser: [Chrome XX | Firefox XX]

• Language: [all | TypeScript X.X | ES6/7 | ES5]

• Node (for AoT issues): node --version = 10.15.1

[rafa-suagu]

I have the same problem using SSR. On the SSR the autocomplete shows null as string but when render the browser side the null is removed.