Issue when the value does not exist in the option is still added to the select box

[robinlieson92]

Describe the bug
Hi, I discovered a vulnerability when I tried to patch data from the API, but data that should not be in one of the options instead appeared in the existing select box.
This is vulnerable to attack via XSS and please follow up further.
I don't know if this can be solved in the same way by still making sure the item in the option is placed in the [items] configuration or not

Reproducbile example
https://stackblitz.com/edit/angular-nckghm-umj73p

Expected behavior
That options other than those entered will not be rendered in the select box and prevent XSS attacks from occurring.

Screenshots